mow“: ‘Ii'.’7;7:.33'i'Y

0F Ad”. u. _ .. . .3 39:25:05

DEPA;-.T;.-ZI-; "r or min/HSTRY
EAST LANSING, MICHIGAN

A KINETIC STUDY CF THE ELECTRCN
EXCHANGE RESCTICN BETWEEN.ANTIECNY(III)
AND ANTIKCNY(V)

By

Joseph A. Sincius

A THESIS

Submitted to the School for Advanced Graduate Studies of
Michigan State University of Agriculture and Applied Science
in partial fulfillment of the requirements
for the degree of

DOCTOR OF PHILOSOPHY

Department of Chemistry

1960

ACKNOWLEDGEMENT

Grateful acknowledgement is hereby accorded
to Professor Carl H. Brubaker for his advice,
guidance, and encouragement; to Mrs. J. A.
Sincius, the wife of the author, for cheer-
fully enduring several bleak and indigent
years, as well as performing countless
enervating statistical calculations; to the
American Viscose Corporation and the
National Science Foundation for financial
aid; and to two wonderful parents and a fine
uncle and aunt who helped to bridge the gap
between stipends and the cost of a spartan
existence.

111

A KII‘~TE'I‘IC STUDY CF THE ELECTRON
EXCELWGE REhC'IICN BETWEEN A:~:‘I‘IMONY(III)
AND ANTIMONYW)

By

Joseph A. Sincius

AN’ABSTRACT

Submitted to the School for Advanced Graduate Studies of
Michigan State University of Agriculture and Applied Science
in partial fulfillment of the requirements
for the degree of

DOCTOR OF PHILOSOPHY
Department of Chemistry

Year 1960

Approved {ARR- IIL‘ ‘WN‘

 

iv

ABSTRACT

The kinetics of the exchange reaction between Sb(III)
and Sb(V) was studied in aqueous sulfuric acid, and in
aqueous sulfuric acid systems containing added chloride ion.
No exchange was observed in aqueous sulfuric acid, but the
addition of chloride initiated exchange, and the concentra-
tion of chloride had a significant effect on the observed
rate. In addition to a study of the influence of chloride
concentration, experiments were performed in which the
effect of independent variation in the concentrations of
antimony(III), antimony(V), sulfate, and hydrogen ion was
determined at two levels of chloride concentration, 6.00 g
and 0.20 y, Supplementary spectrOphctometric examinations
of antimony(III) and antimony(V) solutions were also per—
formed.

In 6.00 g chloride, it was found that the reaction was
first order with respect to antimony(III) and antimony(V),
that sulfate ion has no effect, and that the dependence of
exchange rate exhibits a maximum at approximately 9,§
hydrogen_ion. The exchange mechanism is apparently iden-
tical with that observed previously in hydrochloric acid
solutions.

In 0.20 E chloride, while the rate maintains a unit
dependence with respect to antimony(III), the reaction

V

exhibits a fractional order of 0.76 with respect to anti-
mony(V). At this level of chloride concentration the rate

of exchange is approximately second order with respect to
chloride, but undergoes a sharp maximum at approximately

94E hydrogen ion, and a similar, although much less pro-
nounced maximum at 0.60 E sulfate. The two antimony
oxidation states are apparently involved in complex equilib-
ria with chloride, sulfate, and hydrogen ions. Both chloride
and sulfate are involved in the activated complex, although
the relative importance of chloro or sulfato bridging is
difficult to assess. While some qualitative observations

as to mechanism can be made, a quantitative evaluation must
await a more accurate knowledge of the nature of the solution

species and their equilibrium relationships.

vi

TABLE CF CG NT ENTS

I. INIRODL?CTICNOOOOOOOOOO ..... O ..... OOOOIOOOOOOOOOOOOO
II. HISTORICALQOOOI. ...... 00.00.00.000...00.00.000.000.

A. Electron Exchange................................
B. Antimony Chemistry00000......OOOOOOOOOOOOOOOOO...
C. Antimony(III)-(V) Electron Exchange..............

III. THEORmICALoeeeeooOOOoeooeeoooeoooooeoeoeoo00000000
IV. EXPERIMENTAL PROCEIJREQOeooeoooeeoeoooeeeeeeeoooeo

Materials.0.00......00.0900...OOOOOOCOOOOCOOOOOOI

Antimcny StOCk Solutions...o.........o.......oo..
Solutions for Exchange...........................
Separation of Antimony Cxidatidn States..........
Counting Procedures..............................
Light Absorption Measurements....................
Analytical MethOdSOOOOOOOOOOOOOOOOOOOOOOOOOOOO...

ID"dFHU()U1>

V. RmmTSCOOOOOOOOOOO 00000000 OOOOOOOOOOOOOOOOOOOOOOOO

A. Electron Exchange in Aqueous Sulfuric Acid.......
B. Electron Exchange in Aqueous Sulfuric Acid with

Added Chloride Ion...............................

1. Variation of Exchange Rate with Chloride Ion...
2. The Dependence of Exchange Rate on the concen-

tration Of Sb(III) and Sb(V)eooeeeo.eeoeoooeoee

&. Variation of Exchange Rate with Sulfate Ion....

. Variation of Exchange Rate with Hydrogen Ion...

C. Spectroscopic313116135000ooeeeeeoeoooooeooeooeoeoe

D. Discussion of Errors.............................

VI. DISCUSSION.........UHHH...........................
VII. SUMMARY............................................
VIII. LITERATURE CITED...................................
APPENDIX - ORIGINAL KINETIC DATA...................

vii

7
11

15
17
17
21
26
27
31

33
33

36
36

7
1

52
57
61

61
78

81
88
90
9h

LIST OF TABLES

TABLE Page
I. Exchange Runs in Aqueous Sulfuric Acid......... 38

II. Variation of Exchange Rate with Chloride
concentrationOOOOOOO0.0000000000000000000.00.0. 1+2

III. EXChange at l+200° C. .0.00000000000000000000000 “9

IV. Dependence of Exchange Rate on the Concentration
0f Sb(III) and Sb(V) in 6.00 21 Chlorideooeeoeee 53

V. Dependence of Exchange Rate on the Concentration
of Sb(III) and Sb(V) in 0.20 g Chloride........ 9+

VI. Dependence of Exchange Rate on Sulfate Ion
Concentration in 0.20 M_Chloride............... 58

VII. Dependence of Exchange Rate on Sulfate Ion
Concentration in 6.00 M Chloride............... 60

VIII. Dependence of Exchange Rate on Hydrogen Ion
Concentration in 6.00 E Chloride............... 60

IX. Dependence of Exchange Rate on Hydrogen Ion
Concentration in 0.20 M Chloride............... 63

X. Rate of Exchange of "Standard" Run............. 80

viii

FIGURE
1.
2.

3
u
5.
6.
7.
8.

C
/O

10.
11.
12.
13.

1h.
15.
16.
17.
18.
19.

20.

21.

LIST CF FIGURES

Exchange Rate as a Function of Chloride........
Typical Exchange in 6.00 E Chloride............
Typical Exchange in 2.00 g Chloride............
Typical Exchange in 0.20 3 Chloride............
Exchange in 2.00 E Chloride at h2° C. .........
Exchange in 0.20 E Chloride at h2° C. .........
Exchange Rate as a Function of Sb(III).........
Exchange Rate as a Function of Sb(V)...........
Exchange Rate as a Function of Sulfate.........
Exchange Rate as a Function of Hydrogen Ion....
Ultraviolet Spectra in h.00 _ Sulfuric Acid....
Ultraviolet Spectra in 12.7 M Sulfuric Acid....

Antimony Absorbancy as a Function of Sulfuric

Acid...........................................
Absorbancy as a Function of Sb(III)............
Absorbancy as a Function of Sb(V)..............
Antimony Spectra in Exchange Solution Media....
Sb(III) Absorbance as a Function of Sulfate....
The Effect of Sulfate on Sb(V) Spectra.........

Sb(III) Absorbancy as a Function of Sulfate in
0020£1Chlorideeoeeeoeooeeooeoeococo-0000000000

Sb(V) Absorbancy as a Function of Sulfate in
0.20MChloride...‘COCOCCOOCOCOOOOOCO0.....0000

Sb(III)—Sb(V) Absorbancy as a Function of
Sulfate in 0.20 .M_ ChlorideOOCO0.00.00.00.00...O

ix

69
7o
71
72
73
71+

75

76

77

I. INTRODUCTION

The study of the mechanisms of inorganic reactions
is one of the newest general fields of research in inorganic
chemistry. With the availability of radioactive tracers,
reactions of oxidation - reduction are receiving considerable
attention because it has become possible to study the
electron transfer equilibria between different oxidation
states of the same element. Of particular interest are the
exchange reactions where the net effect is the transfer of
two electrons, since these may proceed either by the simul-
taneous transfer of two electrons, or alternatively by the
stepwise exchange of one electron at a time through the
intermediate oxidation state. The exchange reaction:

Sb(III) + Sb*(V) = Sb*(III) + Sb(V)
is such a two electron transfer system. While hydrochloric
acid solutions and the chloro-complexes of antimony have
been extensively studied, antimony species in sulfate media,
particularly those of the (V) oxidation state, have received
little or no attention. Oxidation - reduction rates are of
particular interest here because of the possibility of
sulfate bridges in the electron transfer, such as have been
postulated in the analagous reactions of Tl(I)-Tl(III) and
Sn(II)-Sn(IV). The kinetics of the Sb(III)-Sb(V) reaction

has been observed in aqueous hydrochloric acid, but the

results were difficult to interpret because of competing
hydrolysis reactions. It was decided to investigate this
reaction in aqueous sulfuric acid, and also to observe the
catalysis by chloride ion in this medium, where competing

hydrolysis reactions should not be a problem.

II. HISTORICAL

A, Electron Exchange

Although most of the reactions in inorganic chemistry
involve oxidation - reduction, the actual mechanism by
which electrons are transferred is unknown. Such processes
are difficult to study because they proceed virtually
instantaneously so that it is impossible to measure a rate,
and the systems are generally very labile with respect to
changes in the coordination sphere, so that intermediate
stages which would supply evidence about the nature of the
activated complex,change to final products too rapidly for
convenient observation. With the availability of radio-
active isotOpes it has become possible to observe electron
transfer equilibria between the ions of a metal in two
oxidation states. These are oxidation - reduction reactions
in which the reactants and products are identical. The
enthalpy change is about zero, but the free energy decreases
by the amount calculated from the entrOpy of mixing. The
entropy at equilibrium when all the isotopes are uniformly
distributed is greater than that of the original system.

Exchange rates for simple ionic species vary tremen-
dously, and are particularly dependent on the presence of
anionic catalysts, such as chloride. Apparently a definite

energy barrier exists between products and reactants, the

height of which depends on the particular exchange system
under consideration.

Libby (1) has discussed these phenomena on the basis
of the Franck - Condon principle. Electron transfer in
aqueous solution should be inhibited by the relatively
longer time required for the movement of the hydration
atmospheres as compared to the transit time for the electron.
The electron must be able to make the transition against a
barrier comparable in magnitude to the amount of energy
involved in the subsequent slow reorientation of the water
molecules to the new charge situation. The catalysis of
small negative ions is presumed to be the result of bridge
formation which causes the two positive ions to approach
more closely, and share their hydration atmospheres to a
considerable extent, so that dissimilarities are reduced.
While a bridging group clearly can function to lower the
potential energy barrier, its exact role is difficult to
define. It may serve as a path for the transfer, the
electron moving through the molecular orbitals of a bridg-
ing group held by chemical bonds to the two exchanging
species, or the process may be atom or group, rather than
electron, transfer.

Marcus, Zwolinski, and Eyring (2) have advanced an
"electron tunneling" hypothesis, in which the electron
leaks through the potential energy barrier in the well

known quantum-mechanical phenomenon. Several layers of

\n

solvent may separate the reactants,and the individual
hydration atmospheres are not disturbed. Systems such as
Fe(cm)6'“- Fe(CN)6'3, Mnog'Z— MnOu', and IrCig'3- Ir016'2
are substitution inert and a bridged intermediate is dif-
ficult to envision, but nevertheless rapid exchange takes
place. These are highly symmetrical reactants, however,
and the rearrangement of the coordination spheres during
and after electron transfer is probably a minimum.

The bridge mechanism of electron transfer has been
supported by the work of Taube (3, h, 5, 6, 7), who
demonstrated that the oxidation of chromium(II) by a variety
of monosubstituted pentamminecobalt(III) species of the type

@o(NHB)5X]+2 takes place with the transfer of X to the
reducing agent, where X has been chloride, bromide, nitrate,
thiocyanate, acetate, perphosphate, and sulfate. Aquo and
hydroxo bridges are also possible. The net atom transfer
in each of these reactions is not necessarily an essential
part of the electron transfer. In a reaction studied between
Cr(II) and IrC16'2, the bridging chloride remained with
Ir(III) rather than Cr(III). The essential feature is that
an appropriate bridge provides a more accessible route for
the flow of electrons, and whether group transfer takes
place depends on the relative substitution lability of the
ions left sharing the bridge after electron transfer.

Systems in which the net result is a transfer of two

electrons have also been studied. Because of the charge

difference of two between the reactants, dissimilarity in
coordination atmospheres will be considerable, and the
energy barrier from the necessary subsequent rearrangement
will be higher. The "tunneling" hypothesis is even less
attractive because quantum mechanical calculations indicate
a very low probability for a simultaneous transfer of two
electrons. Most such two electron exchanges have been
studied in halide or pseudohalide media such as chloride
and cyanide. In Tl(I)-Tl(III) (8), Sn(II)-Sn(IV) (9), and
Sb(III)-Sb(V) (10, ll, 12) exchange equilibria, transition
states which contain two univalent anion bridges are proposed,
and the exchange does not necessarily proceed stepwise
through the intermediate oxidation state. These results
have promoted an interest in the possibility of a single
bridge by a divalent negative ion such as sulfate.

Sulfate bridges have been postulated by Brubaker and
Mickel in the Tl(I)-Tl(III) exchange (13). It is of interest
to note that on the addition of chloride to the Tl(I)-Tl(III)
system in aqueous sulfate (1%), the rate of exchange is
first diminished as the sulfate complexing is replaced by
chloride, and only increases when sufficient chloride is
present to approach the double chloride bridged intermediate
prOposed by Dodson. In the Sn(II)-Sn(IV) reaction in
aqueous sulfuric acid studied by Gordon (15), sulfato species
are apparently the exchanging groups, and presumably sulfate

bridging is involved in the activated complex.

B, Antimony Chemistpy
The first publication on antimony appeared in 160%, and

was attributed to a fifteenth century monk, Basilius
Valentinus. A pertinent quotation from this work, entitled
"The Triumphal Chariot of Antimony is as follows: " But
antimony, like mercury, can best be compared to a round
circle, without and, and the more one investigates it, by
suitable means, the more one discovers in it, and learns

from it; it cannot be mastered, in short, by one person alone
because of the shortness of human life" (16). The enthusiasm
of many experimenters has been blunted on the frustrating
chemistry of antimony.

The chief use of antimony is in alloys, particularly
those with lead, which are employed in batteries, bullets,
and type metal. There has been considerable recent interest
in the application of metal antimonides as transistor and
thermoelectric materials.

Antimony compounds display the anticipated +3 and +5
oxidation states. In the +3 state, antimony is amphoteric,
the trioxide (actually Sbgoé) dissolving in acids or alkalis,
with the isoelectric point at pH 8.6 (17). Little evidence
exists for a definite antimonous acid, precipitates of
hydrous trioxide being obtained (18). The +3 cation forms
a sulfate and nitrate, but only with concentrated acids, and
these are readily hydrolyzed to form the basic antimonyl

salts containing the SbO+ group. The antimonites, commonly

formulated as MSb02, are also subject to extensive hydrolysis
in water. In 2.5 fl KOH an ionic weight in accord with the
formula Sb(OH)g ’ was established by Brintzinger by dialysis
measurements.

According to the position of antimony in the fifth
group of the periodic table, one might anticipate an ortho,

a meta, and a pyroantimonic acid. Hewever, no definite
hydrates of antimony pentoxide have been found (20). Anti-
mony pentoxide apparently can occur with any arbitrary water
content, and the varying properties that have confused
investigators are the result of differences in the method

of preparation.

The salts of antimonic acid were initially regarded as
"meta" salts of the type MSbO3-xHéO, but from the calculations
of Pauling (21), and the x-ray investigations of Beintema
(22), they have been shown to be derived from an acid of the
formula HSb(0H)6. The sodium salt, long known as sodium
pyroantimonate, and assigned the formula Na2H28b207'5320,
is sometimes used as a test for sodium ion because of its
insolubility. That the antimony(V) species present in basic
solution is actually Sb(OH)6' has been shown by the dialysis
measurements of Brintzinger (19), and the spectral studies
of Souchay and Peschanski (22).

If either the trioxide or pentoxide is heated above
300°, the so-called antimony tetroxide is obtained, but the

existence of tetravalent antimony has never been established.

The crystal structure of the tetroxide (SbuOg) is similar to
that of SbTaOu, and contains both Sb(III) and Sb(V) atoms.
The solubility and oxidation state of the tetroxide in water
and in dilute and concentrated acids and alkalis has been
investigated by KonOpik and Zwiauer (25), who concluded that
the tetroxide is present as Sb(III)Sb(V)Ou, although the
exact nature of the species was not established.

. Both oxidation states form a variety of complexes;
those with oxygen, sulfur, and halide donor groups are of
particular importance. Chelate complexes with organic
ligands such as oxalate, citrate, tartrate, and acetylaceton-
ate are well known. Antimony trihalides form a number of
complex halides of the type MSng, M2be5’ and M3SbX6, while
antimony(V) yields halide complexes such as MSbFé, MSbClé,
and MSbBr6. '

The identification of antimony species in aqueous
solution has been rather limited, and the solution chemistry
of antimony is almost entirely that of complexes. As
mentioned above, in basic solution, the dominant species are
Sb(OH)g' and Sb(OH)6‘. The effect on Sb(V) species upon
acidification of basic solutions has been studied Spectro—
scOpically by Souchay and Pesohanski (23), who treated
potassium antimonate solution with acetic, formic, or chloro-
acetic acid until the final solution was l-2Ifl in acid and
12 x 10"3 fl,in antimony. Spectral changes observed with

decreasing pH were interpreted in terms of anionic

IO

polymerization. Antimonate ion was claimed to be Sb(OH)6'
at high pH, and HSb6017'3 at pH values below 2.5; no
appreciable amounts of other ions were shown to exist above
pH = 0.9.

The antimony species that have received the most
attention are those observed in hydrochloric acid media,
since most investigators prefer to work in areas where
solubility problems are not so critical. In high hydrogen
ion, high chloride systems, the dominant Species appear to
be SbClg' and SbClé'.

SbCl6’ has been reported as the polarographically
reducible species in h-6IH HCl, or in 6.x HClOg containing
0.2,3 HCl (26). In the absence of chloride, no reduction
wave other than the hydrogen ion discharge occurs. Similarly,
polarographic data for the reduction of Sb(III) in hydro-
chloric acid indicated that the antimony is essentially all
present as SbClg' (27). The formal potential of the
antimonous — antimonic half-cell for chloride solutions has
been investigated by Brown and Swift (28) who postulated
the following equilibria:

SbClu' + 201' = SbC16' + 2e
spoié- + xHOH = Sb(OH)xC1y' + xH+ + (6—y)Cl'
SbClé' + SbClg' = Sb20110'2

The Spectra of Sb(III) and Sb(V) in hydrochloric acid
solutions have received considerable attention because of

"interaction absorption". Abnormally deep and intense

11

coloration is often exhibited by systems containing an
element in two different oxidation states. Such Optical
interaction has been observed for Sn(II)-Sn(IV), Fe(II)-Fe(III),
and Cu(I)-Cu(II). For Sb(III)-Sb(V), this phenomenon has
been shown to be the result of a dimer between SbClé' and
SbClu' (29, 30, 31), and not a complex of Sb(IV). Additional
spectral studies on Sb(V) species in hydrochloric acid
solutions have been performed by Neumann (32, 33), who
interpreted Spectral changes with decreasing hydrochloric
acid concentration as the stepwise hydrolysis of SbClg',
yielding equilibria involving Sb(CH)ClS’, Sb(OH)QClg’, and
Sb(OH)3Cl3'. Sb(OH)015' is the predominant form in 8 M

acid, and Sb(OH)2Cln' in 6|! acid. Sb(OH)3Cl3' and more
hydrolyzed species are the most important in acid concentra-

tions below 5 g,

C. AntimonySIIIz-gvz Electrog Exehange

Antimony(III)-(V) electron exchange has been investigated
in aqueous hydrochloric acid by Bonner (10), who examined
the system principally in 64$ hydrochloric acid at 25°C.,
and derived the empirical rate law:

R = (8.8 i 0.9) x 10"11E‘>IL>(III)]O-6 [sum] 1'1 [911951 8‘
While Bonner prOposed no mechanism for the exchange, his
results indicated that the interaction dimer observed in
Spectroscopic studies was apparently not the primary

activated complex in 6lfl HCl, although formation of the dimer

12

could be a rate-determining step in one of several exchange
processes.

Cheek (11) observed the exchange in the hydrochloric
acid concentration range of 6-12 h, and found unit Sb(V)
dependence, but an Sb(III) dependence which decreased from
unity in l2,fi acid to 0.9 in 9.5LE_HC1, a difference which
was felt to be real. In Arnie HCl, a dependence of 0.8 was
indicated, although experimental error was estimated to be
at least 20% in this set of determinations. Although insuf-
ficient data were collected to make an estimate of order,

a marked increase in the exchange rate with increasing
chloride (6-10.6 g) at hydrogen ion concentrations of
approximately 6 E was observed, while increasing hydrogen
ion from %.3 to 6.8 y’at 9.5 fl total chloride resulted in a
slight decrease in rate.

Cheek attempted to relate Sb(III)-Sb(V) interaction
Spectra with exchange rates, but concluded that the exchange
proceeds by several paths, some of which do not involve the
interaction complex. The decreasing dependence of the
exchange rate on the Sb(III) concentration with decreasing
hydrochloric acid was explained as the consequence of slow
interconversion of several forms of Sb(V) at equilibrium.

Neumann has studied the equilibrium (32) and kinetic
(33) behavior of Sb(V) in hydrochloric acid solution, and
has correlated this work with the results of Bonner and

Cheek, as well as performing some new exchange experiments (12).

13

The observed complexities of the exchange reaction were
interpreted on the assumption that SbClé' is the only species
that exchanges with Sb(III), and that in more dilute hydro-
chloric acid solutions the rate determining step is the
formation of SbCl6‘ and not the exchange process. Experiments
performed under non-equilibrium conditions where all the

Sb(V) was initially present as SbClé' indicated that the

rate of exchange decreases with increasing acidity. In
studying the kinetics of the hydrolysis of SbClé', the Sb(III)
catalysis that had been observed was attributed to the
ability of the Lewis acid SbCl3 to abstract a chloride ion
from SbClg'. SbCl3 was also postulated as the exchanging
Species of Sb(III) instead of SbClh’, because decreasing
acidity leads to a more rapid exchange between SbClo’ and
Sb(III), and the formation of a transition state between a
neutral molecule and an anion is more probable. Neumann
suggests transition states for the exchange such as :

Cl\ l\

SbCl3' and C13Sb1g—SbCl3'

Clqu/ 1
\oi/

\Cl/

Two additional Sb(III)-Sb(V) systems have been studied
by Turco, who observed the effect of bromide in 3.2 molal
H01 (3%). The rate constant at 26° was found to be given

by the expression:

k = (ban 1 0.2)x10')+ Eb(III)]"’C-15[Sb(V)] 1.1 [Br-]3.5[H+]l+.2 ‘

1%

The fractional orders observed were not explained, a not
unexpected consequence since the system is sufficiently
complex in HCl without introducing bromide as another
variable.

In 1.8 fl KCH, no exchange was observed between

antimonite and antimonate (35).

III. THEORETICAL

The exponential rate law which governs the appearance
of radioactive atoms in the initially untagged species has
been derived by McKay (36), and in its logarithmic form
appears as follows:

1n(1-F) = —R :+b t , where:

observed rate of exchange
total concentrations of the reactants
fraction of exchange, x/x«, with:
x = specific activity at time t in
initially untagged species
xw.= specific activity at time t» in
initially untagged species

9.)
"IJU‘DU
II II II

This exponential law is followed regardless of the
mechanism by which exchange occurs, the number of exchangeable
atoms in each species, or the concentration of the radio-
active atoms. The only restriction in its application is
that the exchange reaction must occur in a stable, homo-
geneous phase, and that the atoms of each oxidation state
are either chemically equivalent or are involved in an
equilibrium among themselves which is rapid compared to the
rate of exchange. A plot of ln(l-F),1e‘ t will be linear
for the entire run, and B may be calculated from the slope.
The great advantage in the study of exchange kinetics as
OppOSed to the kinetics of ordinary chemical reactions is
that R is evaluated from the entire run, and not from an

extrapolated point.

16

More conveniently, t% can be obtained graphically, and

R evaluated from a derived relation:

_ 0 6 ab
R ’ fiti‘

To determine the reaction order with reapect to the
reactants or any other species, general kinetic procedures
are applied. The rate may be typically given by a relation
such as:

R k(a)d(b)o(c)x

The concentrations of a, b, and c may be independently
varied, and 0< , (5 , K , the orders of the reaction with respect
to the individual reactants evaluated, e.g., from the slope

of the plot of log R ye. log (a) :

(".3 .log RT} .—. o<
6103(8 (b)(C)

Since it is necessary to apply a chemical separation
method, transitory intermediates may form which exchange
more rapidly than the homogeneous system. Prestwood and
Wahl (37) have shown that in the semi-log plot of (l-F) 1;.
t, while the intercept will not be unity, the slope will not
be affected, so that t8 and B may be correctly evaluated.

IV. EIIPEE‘LII-EWTAL PROCEDURES

Ax,Nateriele_

The antimony metal and antimony trioxide employed were
the Baker and Adamson reagent grade product, while the
sulfuric and hydrochloric acids were reagent grade materials
purchased from E. I. du Pont de Nemours and Company.
Perchloric acid was obtained from the Mallinckrodt Chemical
Works. Lithium perchlorate was prepared from Mallinckrodt
reagent grade lithium carbonate, a slight excess of which
was added to reagent perchloric acid, recrystallized as the
trihydrate, and dried over anhydrous lithium perchlorate.
Where lithium perchlorate was necessary in preparing
solutions for exchange, it was weighed directly, but in
general, where possible, the use of lithium perchlorate was
conveniently avoided by the judicious combination of
perchloric acid and lithium chloride solution, prepared from
Mallinckrodt analytical reagents, and standardized by tit-
ration with silver nitrate. Lithium sulfate monohydrate
was the Fisher "Certified" analytical grade material. The
"thionalide",e<-mercapto-N-2-naphthylacetamide, was Eastman
Kodak #5828, while the 8-hydroxyquinoline (8-quinolinol) was
Eastman #79M. The cupferron, ammonium nitrOSOphenylhydroxyl-
amine, was "Baker's Analyzed" reagent grade. All of the

other analytical reagents and chemicals employed in this

18

work were reagent grade materials from reputable suppliers,
and were used without additional purification, except perhaps
for a routine drying Operation for the primary analytical
standards.

The antimony tracer used in the exchange experiments
was Sb125. This nuclide decays to an excited state of its
daughter Te125 with a half-life of 2.7 years. iaximum 63
energies observed and their distribution are 0.128 Nov 33%,
0.299 Mev hgz, and 0.616 Nev 18%. Associated I energies
are 0.035, 0.110, 0.175, 0.h25, 0.001, and 0.637 Mev. The
metastable daughter nucleus attains its ground state by
isomeric transition with a half-life of 58 days through
emission of 0.035% and 0.109 Mev K'radiation.(38).

Three SblZS activity units were obtained from the Cak
Ridge National Laboratory, each containing 0.% millicuries
of Sb125 in 6.2 grams of metallic tin that had been

subjected to neutron irradiation for 28 days.

 

(3’ -
Snmhsmnm 30 minutesr 510125
10 days

Separation of the Sb125 from the gross amount of tin
was accomplished by fractional sulfide precipitation from
a medium in which the tin was present as the oxalato Sn(IV)
complex (39, %0, %l). Since each unit contained only
approximately 3.8 x 10"7 grams of Sb125 in 6.2 grams of tin,

it was necessary to employ isotopic carrying. The procedure

19

followed is outlined on page 20.

Each unit was dissolved in 25 ml. of concentrated
hydrochloric acid, 5 ml. of 12 E_sulfuric acid solution
containing 0.022 grams of antimony were added, and the tin
oxidized with elemental bromine. A hot solution of 120
grams of oxalic acid dihydrate and 20 grams of potassium
hydroxide in 100 ml. of water was added, and the antimony
was precipitated by hydrogen sulfide by a pressure technique
(%2). The antimony sulfide was separated and washed by
centrifugation. Another addition of antimony carrier was
made to the mother liquor, and a second sulfide precipitate
collected. The combined sulfides were dissolved in 5 ml.
of concentrated sulfuric acid, and reprecipitated from a
medium containing 10 grams of oxalic acid dihydrate in 100
ml. of solution.

The combined sulfides from all three units were dis-
solved in 30 m1. of hot, concentrated sulfuric acid, yielding
an Sb125 stock solution which contained approximately 0.15
grams of antimony in 25 ml. of concentrated sulfuric acid.

An aluminum absorption curve was determined for the
product, and yielded a range of 220 mg./cm.2, corresponding
to a maximum (3 energy of 0.61 Mev (%3). A half-life for
the isotope was established employing a National Bureau
of Standards RaD-RaE standard. This determination was
rather inadequate, decay being observed for a period of only

8 months, but the data yielded a value of 2.6 years, which

 

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21
agrees as well as can be expected with the accepted value.

B. Antimony Stoek Solutions

Antimony metal was dissolved in hot, concentrated,
sulfuric acid. The white, crystalline antimony(III) sulfate
which precipitated on cooling was separated by filtration
through fritted glass, and was recrystallized twice from
concentrated sulfuric acid. Antimony(III) stock solutions
were prepared by adding an excess of antimony(III) sulfate
to hot 12 fl sulfuric acid, cooling the solution to room
temperature, filtering through fritted glass, and adding a
small amount of 12 g sulfuric acid to the filtrate to avoid
saturation effects. Two such stock solutions were prepared,
and contained 0.0368 and 0.0595 fl,antimony(III) in 12.76
and 12.7% g sulfuric acid, respectively.

In order to obtain solutions in this concentration
range, any hydrolysis of antimony(III) must be avoided. If
the antimony(III) sulfate is hydrdlyzed with water, or if
the starting material is antimony trioxide instead of the
metal, maximum antimony concentrations that are realized
are of the order of 0.01 E, and a solid phase separates
slowly, even if the hydrolyzed sulfate or reagent grade
antimony trioxide is digested with hot, concentrated,
sulfuric acid for extended periods. Solutions prepared as
described above, however, have been stable for more than

a year.

f‘ )
h.)

The classical preparation of the +5 oxidation state
involves the chlorine oxidation of antimony(III) in hydro-
chloric acid solution (%%, %5). This route was initially
avoided because of the difficulty of removing traces of
chloride from the hydrolyzed product and the need to avoid
any possibility of chloride contamination in the exchange
experiments in aqueous sulfuric acid which were the primary
objective. However, neither the reaction of metallic
'antimony with concentrated nitric acid nor the oxidation of
of a hydrobromic acid solution of antimony trioxide with
elemental bromine resulted in quantitative conversion.
Antimony(V)/antimony(III) ratios of about two forced
acceptance of the chlorination procedure until a superior
technique was evolved.

Antimony trioxide was dissolved in concentrated hydro-
chloric acid, filtered through hardened Whatman #50 paper,
and treated with purified chlorine for several hours. The
color of the solution proceeded from a light yellow to a
dark orange, to a pale greenish-yellow. These transitions
are apparently the result of Sb(III)-Sb(V) interaction
absorption in hydrochloric acid (29, %6), which disappears
as the oxidation goes to completion. The solution was
concentrated, cooled in an ice-salt bath, and saturated for
three hours with hydrogen chloride generated from concentrated
hydrochloric and sulfuric acid. A dense deposit of white

crystals of hexachloroantimonic(V) acid separated. These

23

were collected on fritted glass, washed with ice-cold
hydrochloric acid, and recrystallized twice from hydrochloric
acid by cooling and resaturating with hydrogen chloride.
The product remained crystalline only when cold, degenerating
into a soupy slurry at room temperature. The hexachloro-
antimonic acid was hydrolyzed with water, and washed by
digestion and decantation with fifteen 1500 ml. portions of
water over a period of three weeks. Peptization difficulties
were avoided by acidifying the wash water slightly with
sulfuric acid. Even after this extensive washing, the
supernate yielded a qualitative test for chloride. The
hydrolyzed material was collected on a filter, washed into
a two liter, round-bottomed, two neck flask, 250 ml. of
concentrated sulfuric acid were added, and the mixture was
heated to 1%0-150 °C. while being agitated with a slow
stream of nitrogen. Water was periodically added to the
pot, while the distillate was analyzed for chloride by
addition of silver nitrate and comparison with 0.1 and 1.0
p.p.m. standards in Nessler tubes. After 2300 ml. of
distillate were collected in this manner, chloride tests
were finally negative. The filtered product was a white,
viscid semi-solid (20), which was converted to a white
powder after drying at 110 °C. Oxidation state analysis
indicated a complete conversion to antimony(V).

Because of its solubility, or slow solution kinetics,

preparation of solutions of this material was difficult.

2%

It did not dissolve appreciably in concentrated hydrochloric
acid, nor did it dissolve completely in boiling, concentrated
sulfuric acid in finite time, except for one fortuitous and
never duplicated combination of conditions, when complete
solution occurred, yielding an antimony(V) concentration of
0.108 M. Other antimony(V) solutions in sulfuric acid were
prepared by heating the product with acid, removing undis-
solved material by filtration, and concentrating the filtrate.
Completely stable solutions up to 0.079 M antimony(V)
prepared in this manner were used in some early spectral
work, but not in any exchange studies.

The method just described for obtaining sulfuric acid
solutions of antimony(V) is circuituous, tedious, and
vulnerable to criticism as to trace chloride impurities.

An optimum technique was found where the antimony(III) was
oxidized to antimony(V) ;Q.e;§e, utilizing the mixture of
peroxydisulfuric acid and its decomposition products,
peroxymonosulfuric acid and hydrogen peroxide, that results
from the electrolysis of sulfuric acid solutions.

Peroxydisulfuric acid was produced by a high current
density anodic oxidation of sulfuric acid (%7, %8, %9, 50).
The anode was a one centimeter length of heavy platinum wire;
the cathode was a 15 centimeter spiral of finer platinum.

The source of potential was a six volt automobile storage
battery used at full capacity. The 9 M sulfuric acid

electrolyte, cooled in an ice bath, was electrolyzed at 1.5

\)
\n

amperes for eight hours. Current efficiencies of approximately
33% were obtained, based on total oxidizing power of the
product solutions.

Immediately after preparation, the "peroxy acid" was
added in 2-300% excess to antimony(III) solutions in 12 E
sulfuric acid, and the mixture allowed to stand for twelve
hours. Gentle heat was applied until oxygen evolution
ceased, then increased in intensity to concentrate the
antimony(V). Unless the antimony solution was extremely
dilute, the increase in heat resulted in the appearance
of a fine, white, solid phase, which slowly dissolved.

Stock solutions of antimony(V) prepared in this manner
yielded antimony concentrations of 0.05-0.08 5, although
higher concentrations could be attained with no precipitation
difficulties.

The normal procedure in electron exchange studies is
to prepare a solution of the two oxidation states, allow
them to equilibrate, and take zero time as the moment of
addition of a small amount of tracer. This technique
presumes that the exchanging species in the gross mixture
and the tracer stock solution are identical, or reach
equilibrium instantaneously. Because of the complexities
:hiherent in the antimony(III)-(V) system, such an assump-
tion appeared unwarranted, so that antimony(V) stock solutions
for exchange work were prepared with 513125 initially present.
IUI appropriate quantity of Sb125 solution was added to '

26

antimony(V) in sulfuric acid solution, and the "peroxy acid"
oxidation process repeated. The product was diluted with
6 fl_sulfuric acid to yield an antimony(V) in approximately

12 M sulfuric acid stock, containing the necessary Sb125
tracer, suitable to be used in the preparation of the final

exchanging solutions.

C. Solutions for Exchange
For each kinetic run two individual antimony(III) and

antimony(V) solutions were prepared in 50 ml. volumetric
flasks. Each pair was identical in all respects except
antimony content. The order of addition of components, when
used, was always the same, as follows: solid lithium per-
chlorate trihydrate, solid lithium sulfate monohydrate,
'water, hydrochloric acid, lithium chloride solution, perchloric
tacid, sulfuric acid, antimony(III) or antimony(V) stock
solution, and finally, after temperature equilibration,
water to volume. The solids were weighed to the tenth of a
milligram on the analytical balance, while the calculated
amounts of each stock solution were added from clean, dry
‘Uurets, whose stopcocks were lubricated only with the
solution to be added. The exchange solutions were equili-
brated at constant temperature for at least twelve hours

after preparation, and mixed at zero time.

27

D. Separation of Antimony Oxidation States

In the observation of the kinetics of the exchange,
the tracer was always present initially in the (V) state.
Antimony(III) was separated at definite time intervals, and
the growth of activity observed, since this technique offers
the least probability for separation-induced exchange due
to transitory complexes and separation intermediates (51).
While antimony(III)-(V) separations have been utilized in
previous exchange investigations, this study presented the
unique problem that the antimony solutions were 10-100
times more dilute. It was necessary to be able conveniently
to separate, mount, and count approximately 5 x 10“3 milli-
moles of antimony(III). Three distinct separations were
used, two of which involved 8 counting of a gravimetric
precipitate, while the third was based on liquid phase 3'
scintillation counting of an antimony(III) extract.

The first method evolved employed "thionalide", the
IG-aminonaphthalide of thioglycollic acid, to precipitate
the antimony(III) thionalate, Sb(Cl2H100NS)3 (52, 53, 5h).

.JVH-g-CHZ-SH

"Thiogalidg"

Tile reagent behaves in a manner analagous to hydrogen
Slllfide, cations forming insoluble sulfides, in general,
fibrm insoluble "thionalates". The precipitation of antimony(V)

‘flas prevented by the formation of the hexafluoroantimonate(V)

28

complex with potassium fluoride. The advantage of this
reagent is the bulky nature and high molecular weight of the
precipitate. The chief disadvantage is its sensitivity to
oxidation, an insoluble disulfide being formed, the presence
of which prevents direct gravimetric determination of
antimony recovery.

The precipitate was separated by filtration through
22 mm. Whatman ##2 paper on a stainless steel filter with
a removeable chimney to facilitate mounting of the sample.
Since antimony(III) thionalate is readily soluble in acetone,
it was easily possible to dissolve the precipitate, destroy
the complex by nitric-sulfuric digestion, and determine the
antimony colorimetrically by the tetraiodoantimonate method
(2122.12222). Separation and recovery of the antimony(III)
'was in excess of 99%.

The thionalide method was successfully applied to
exchange studies in aqueous sulfuric acid media in which
no electron transfer occurred. When systems with chloride
present were studied, it was necessary to abandon the method
because induced exchange became a problem (>50%), and also
‘axtensive oxidation of the reagent resulted in increased and
Inireproducible contamination of the antimony(III) thionalate
Vfilth disulfide, leading to inconsistent self-absorption
errors in the counting procedure.

The second gravimetric separation that was applied was

theuse of 8-hydroxyquinoline to precipitate the antimony(III)

29

oxinate (5h, 55), a method that has been successful in other
antimony exchange systems (3, 3h). Oxine precipitation,
however, was not sufficiently sensitive in this concentration
range, and it was necessary to supply additional antimony(III)
as a carrier. Induced exchange again became a problem in

the presence of appreciable chloride, although the technique
was quite satisfactory in low chloride systems. Filtration
and mounting were accomplished as described for the thionalide
separation.

The successful separation that was employed in all
exchange runs for which rates were determined involved the
precipitation of antimony(III) with cupferron (ammonium
nitrOSOphenylhydroxylamine)(56, 57). Antimony(V) is not
precipitated by this reagent. Since a gravimetric separation
‘would be inaccurate because of the small particle size of
the precipitate, uncertainty in its composition, and its
instability, the antimony(III) cupferrate was extracted with
chloroform (58), and an appropriate aliquot taken for 3'
counting. Induced exchange was a minimum.

The cupferron was freshly prepared as a 1% aqueous
tnblution at least every eight hours, and maintained at 0 °C.
1K3 avoid decomposition. A 5 ml. aliquot of the exchanging

SC>lution was pipetted into a 125 m1. separatory funnel

containing 70 ml. of ice-cold water and 5 ml. of reagent
solution, and the mixture agitated; antimony(III) cupferrate
precipitated. The mixture was then shaken for 30 seconds
with 5 ml. of reagent grade chloroform, and the phases
allowed to separate for two minutes. The chloroform extract
was filtered through a glass wool plug into a 10 m1.
volumetric flask. An additional 5 ml. of cupferron reagent
were added to the separatory funnel, and the mixture again
extracted with # ml. of chloroform. After a third extrac-
tion with 1% ml. of chloroform, the glass wool plug was
washed with % ml. of fresh chloroform and the extract made
up to volume. A h ml. aliquot of the solution was pipetted
into a one dram screw cap vial. To prevent loss of chloroform
by evaporation and consequent variation in counting geometry,
it was necessary to seal the vials by stoppering them with

a cork cut off flush with the top of the vial, coated with
Goodyear "Pliobond" adhesive, and covered with a circle of
aluminum foil before the cap was screwed on tightly.

It was essential to use an ice-cold aqueous phase
because the extracted antimony(III) cupferrate complex is
rust stable, and there is a possibility of decomposition and
'qbleed back" into the aqueous phase (59). Similarly, the
aritimony(III) cupferrate solution in chloroform decomposes,
a solid phase separating in a manner of minutes if the
S<>1ution is kept at room temperature. It is impossible to

Seecure a representative aliquot for counting if there is

31

even a slight turbidity present. Extracting a cold aqueous
phase, however, yields a chloroform solution stable for at

least fifteen minutes.

E C nti P o u e

The filter papers with the thionalide or 8-hydroxy-
quinoline precipitates were mounted under cellulose film
on cards out to fit the plastic holder of an R. C. L. steel
castle, and counted in the center of,and two cm. below,a
2.7 mg./cm.2 G-M tube monitored by a Nucleur Corporation
scaling unit (Model 163). When the equipment became available
shortly after the inception of this work, (3 counting of the
solid samples was accomplished with a Baird Associates -
Atomic Instrument PrOportional Counter and a mylar window,
gas flow tube. In all such samples,activities observed were
very low so that no correction other than that for background
was necessary.

All of the kinetic runs where significant exchange was
observed were counted in new, one dram, screw cap vials,
sealed as previously described, in a well-type NaI(T1)
scintillation counter. Because of the essentially h'fl'
geometry and efficiency of scintillation detection, only
background corrections were applied. A minimum of 10,000
cwrunts were registered for each sample. Since all the

Samples from individual runs could be easily counted within

'th0 hours, no correction was necessary for the decay of Sblzs.

32

It is customary to obtain equilibrium activities when
t =co for McKay plots by taking samples after 10 half-lives.
A calculated equilibrium activity was used in this project
because of the long half-lives encountered, and also because
of the non-linearity of the McKay plots observed under some
circumstances. In general, kinetic runs were sampled for
approximately two half-lives, and 8 - 1% samples were
obtained. Beyond two half-lives, or (l-F) values of 0.200,
errors in radicassay increase appreciably (15, 68), and
small errors in the rather involved separation technique
introduce considerable scatter in the points of the McKay
plot.

Equilibrium activities were calculated from the follow-

M

ing relation:

Aq,= equilibrium activity at t = 00
A0 = observed activity of an equivalent aliquot
of the exchanging solution
M3, M5 = molar concentrations of Sb(III) and Sb(V)

respectively

Three samples were taken from each run for equilibrium
activity calculations, and were mounted in a manner identical
‘to that of the kinetic Specimens. The three equilibrium
a<3tivity samples were counted at the beginning, at the half-

Way point, and at the end of a kinetic run sample counting

Sequence. The average of all these results yielded A0.

33

Although the volumetric equipment used in taking these
standard samples was deliberately varied, the observed
activities agreed within counter statistics. This technique

also served to monitor the counting equipment for drift.

F.4§ight Absorption Measurements

Absorption spectra for qualitative or semi-quantitative
purposes were recorded on a Beckman DK-2 recording Spectro-
photometer. All quantitative measurements were obtained
with a Beckman model DU spectrOphotometer equipped with a
photomultiplier tube and a line-Operated, constant voltage,
D.C. power supply. Since all spectral studies were made
below H00 mug a hydrogen discharge lamp served as the light
source. Glass-steppered, matched quartz cells with 10 mm.
light paths were used, with distilled water as the reference
solvent. All sample absorptions were corrected by simul-
taneous blanks on the appropriate media in which antimony

absorption was being observed.

G. Analytical Methods
Acid solutions were standardized by titration with
half-normal, carbonate-free sodium hydroxide solution, which
thad been standardized with potassium acid phthalate and
Stored in a paraffin-coated bottle protected from the
atmosphere by an ascarite guard tube. To avoid errors from
‘t<>o many volumetric Operations, 500 or 1000 A portions of

‘tfle fairly concentrated acid stock solutions were measured

3w

by Research Specialties Co. "Lambda-Pettes" which are cali-
brated to contain, not deliver, thereby avoiding viscosity
effects and drainage errors.

Antimony solutions were analyzed by titration with
decinormal potassium bromate, prepared from oven-dried,
primary standard reagent. Titrations were performed in
2.3 E hydrochloric acid solution, with naphthol blue-black
as an irreversible indicator (6C). Antimony(V) was deter-
mined by reduction with sodium sulfite, evolution of excess
802 by boiling, and bromate titration. For samples requiring
more than 5 m1. of titrant, a 10 ml. buret calibrated every
0.05 ml. was employed, while a micro-buret calibrated every
0.01 ml. served in semi-micro work. The colorimetric
tetraiodoantimonate method which is based on the light
absorption of the Sblg’ complex ion, was applied to small
quantities of antimony (61, 62). The colorimetric reagent
is a concentrated potassium iodide - ascorbic acid solution,
the ascorbic acid serving to reduce any iodine liberated
by oxidizing agents in the sample. Absorption measurements
were taken at #25 MALXQ. a reagent blank, and the system
followed Beer's law in the concentration range considered
(0.1 - 3 x 10'3 millimoles Sb/SO ml.).

Chloride determinations were made by the Caldwell -

Phoyer modification of the Volhard method (63). Where
‘alitimony was present in chloride titrations, it was complexed

Vvisth tartaric acid. The silver nitrate solution was

35

standardized gravimetrically as silver chloride, and
volumetrioally by titration of aliquots of standard sodium
chloride solution.

Sulfate was determined gravimetrically as barium
sulfate which was ignited in platinum crucibles. When

necessary, antimony was removed as the metal on fine iron

wire.

36

V. RESULTS

A, Electron Exchange in Aqueous Sulfuric Acid

The initial purpose of this study was to examine Sb(III)-
Sb(V) exchange in aqueous sulfuric acid. Considerable
difficulty was experienced with precipitation from mixed
Sb(III)-Sb(V) solutions. This phenomenon was a function of
Sb(III), Sb(V), and sulfuric acid. In 12,5 sulfuric acid,
Sb(III)-Sb(V) mixtures in all proportions up to individual
concentration maxima of 0.02 M have been stable for one
year. As the acid is diluted below 9 M, precipitation
occurs from mixtures of Sb(III) and Sb(V) solutions which
are individually stable.

A survey was made in which Eb(IIIj , Eb(V3 , and
FQSOQI were varied. The precipitates were collected on
fritted glass, and the filtrates and precipitates analyzed.
The maximum compatible concentrations of Sb(III) and Sb(V)
that are stable, or at least metastable, in 3-9 M_sulfuric
acid are approximately 3-h x 10‘3 g. The conditions for
precipitate formation were difficult to establish because
the process is a function of time. Clear filtrates slowly
.Separate additional solid phase. All the precipitates

<3cmtained equimolar quantities of Sb(III) and Sb(V).
Sulfate ion was present, but not in any discernible stoichi-

cunetric proportion, and may have been the result of

37

adsorption and occlusion of sulfuric acid on the bulky and
amorphous precipitates. These had been sucked dry in the
vacuum filtration process, but were not washed because of
the danger of peptization and fear of hydrolysis.

With the 1-1 Sb(III)-Sb(V) ratio, no great imagination
is necessary to postulate [Sb0:HSb(0HEfl to be the composi—

ion of the precipitates. The elimination of three molecules

of water from this "antimonyl antimonate" yields the formula
for the tetroxide, szou. The absence of sulfate in the
precipitates, however, has not been established. Spectro-
scopic evidence (yids infra) indicates that Sb(V) Species
in aqueous sulfuric acid are involved in complex equilibria.
These may involve Sb(SOg)3', Sb(OH)6‘, and the obvious
intermediates. The rapidity of precipitation is an inverse
function of the sulfuric acid concentration. Continuing
precipitation with time may be the result of the slow
formation of additional Sb(OH)6-.

After these preliminary observations, the exchange
reaction between Sb(III) and Sb(V) was studied in the
acid range 3-12 5. In no case was exchange observed.
The systems examined are given in Table I.

B, ElectrongExchan e in Alnggns Sulfuric Acid with
Added Chiogidg Ion

The lack of exchange observed in aqueous sulfuric acid

 

Vnas dissappointing, but it did present the Opportunity to

iriitiate exchange by appropriate modifications. Addition of

TABLE I

38

EXCHANGE RUNS IN AQUEOUS SULFURIC ACID

 

 

 

P2801; EbUIIfl [Sb(lq Hours Comments
M M M Observed
2.97 2.h0 2.39 133 No exchange. Precipitate
x 10'3 x 10’3 observed after 800 hours.
3.99 2.h0_ 2.39 3 813 No exchange. Slight
x 10 3 x 10' precipitate observed
after 1600 hours.
6.00 2.’+O_3 2.39_3 1588 No exchange.
x 10 x 10
6.00 5.00 k.77 82 No exchange. Slight
x 10'"3 x 10"3 precipitate observed
after 150 hours.
8.96 2.50 2.39 73 No exchange. Slight
x 10"3 x 10'3 precipitate observed
after 150 hours.
12.0 2.50 2.39 15%9 No exchange.
x 10’3 x 10'3
11.9 10.2”3 10.7_3 787 No exchange.
x 10 x 10

chloride ion was the obvious choice, since Sb(III) and Sb(V)
do exchange in hydrochloric acid, and chloride has a
pronounced catalytic effect in many exchange systems.
Preliminary experiments in which hydrochloric acid was added
indicated that chloride did indeed promote exchange, sug-
gesting a study of the process in such chloride containing
media.

Since the exchanging Sb(III) and Sb(V) species were
certain to be involved in complex equilibria, constant ionic
strength was maintained in an attempt to eliminate activity
coefficients as variab es. Whether the principal of ionic
strength as originally defined by Lewis and Randall (6%)
applies is open to considerable question, since the system
is hardly a dilute electrolyte. However, maintenance of
constant ionic strength should be subject to less criticism
than its neglect, and some concession to thermodynamics
should be made in a kinetic study.

Choice of an ionic strength also was required because
of the necessity to consider the dissociation of bisulfate
ion in the calculation of the concentration of the species
present. The second ionization constant of sulfuric acid
is defined as:

K : (aH+)(aSOg:>
2 (aHSOh‘)

 

For concentration calculations, it is necessary to

#0

apply the concentration "equilibrium constant", K2c:

K __ if? ‘Egsqu
2c - On-

which is related to the thermodynamic dissociation constant
by:
(xgsour)

Values ofXR and K2c at various ionic strengths were

: K2c XE

 

K2 = K2c

available from the Raman data of Smith (65) and Maranville
(66), based upon K2 at 25° = 0.010%, and concentration
calculations were made according to the method of Young and
Blatz (67). Necessary assumptions were that HCl and HC1(;'
were equivalent, that these components as well as the salts
lithium sulfate, lithium chloride, and lithium perchlorate
which were occassionally necessary to maintain ionic strength
‘were completely ionized, and that the correSpondence of the
dissociation constant of bisulfate ion to the ionic strength
is not altered by their presence.

In general, ionic strength (molar scale) was maintained
at 10.5, with Kgc = 3.19. In the study of the effect of
hydrogen ion and of sulfate on the rate of exchange, it was
sometimes necessary to vary the ionic strength to provide
a significant concentration range of the species being
investigated. In such cases, the appropriate value of K2c
from the data of Smith was applied, and any such deviation

is noted in the tables of data. The concentrations of

Ml

Sb(III) and Sb(V) were always negligible in comparison to
the other Species present, so their contribution to the
ionic strength was neglected. Temperature was maintained
at 2H.80 i 0.02 °C. for all runs, except for one series

at an elevated temperature.

1. Variation of Exchange Rate with Chloride Ion

The effect of chloride ion on the exchange rate was
investigated in the concentration range 0 - 6 M chloride.

The sum of hydrochloric and perchloric acid concentrations
was maintained at 6.00 E, so that for any exchange run:

fl HClOg = 6.00 -,§ HCl. The exchange rate, R, was calculated
from the half-times obtained from plots of log(l—F) gs. t.
The data are presented in Table II. In Figure l, the log-log
plot of R yg. chloride concentration, the rates of duplicate
runs are averaged when they are in close agreement.

The log-log plot of R gs. chloride, although reasonably
linear for low chloride concentrations, indicates a
continuously decreasing chloride dependence. The slope was
statistically evaluated for arbitrary portions of the curve,

with the following results:

 

i212 Range £21922
c~.025-o.2o p 2.05
0.15 -O.6O g 1.u1
0.50 -1.50 g 0.82

1.50 “6.00 Ce28

l3

#2

TABLE II

VARIATION OF EXCHANGE RATE WITH CHLORIDE CONCENTRATION

 

 

 

11:10.5 =3.19. [n+1 =9.75JM_,_ [SOLE] =[o.7t+1$ Bison-l

=2.271/ [H§1+§03=3.c_:~§_., 010,-] (6.00- [Ci] M314 M,

[Sb(IIIIT - 1.31 x 10 _, so( )3 = 1.30 x 10 1
E13 ti R

g (hours) (moles/liter-hour)

None (a) No exchange observed in 1790 hours.
0.025 (a) 7, 522 5099 X 10-
0.05 (a) £088 2.20 x 10'7
0.10 (a) 21163 9.72 x 10'7
0.15 (a) 173 2.60 x 10'6
0.20 (b) 118 3.82 x 10"6
0.3g (a) 66.3 6.79 x 10'?
Co (a) 909 1013 X 10-:
o. to 0.1 1.13 x 10"
0. 50 (a) 31.7 1.h2 x 10"5
0.60 (a) 23.3 1.9 x 10'5
o. 60 25.9 1.7 x 10'5
c .70 26.7 1.69 x 10-5
0. 80 21.2 2.13 x 10'5
1.00 20.6 2.20 x 10'5
1.50 12.0 .77 x 10'5
2.00 11.2 .02 x 10"5
2.00 10.8 n.19 x 10'5
2eOO 1006 ue27 X 10-5
2.00 10.2 u.u3 x 10"5
3.00 (a) 10.2 h.u2 x 10‘5
n.00 (a) 9.33 t.83 x 10-5
5.00 (a) 8.75 5.15 x 10‘5
6.00 6.10 7.h1 x 10'5
6.00 7.62 5.93 x 10'5

(a)

(b

)

[Sb(V)] = 1.29 x 10-3 M
Average of 11 runs (see Table X)

 

Q

 

 

 

l+3

 

 

10 _
g -
6 I
5 " 656 99V
’4- r- , "O." D
5 3 r ’
10 R
2 +— 06
00‘
E /’,’O
‘: //Kj
C O/B
+— //
_ //
I O
._ /
E /A
t /
V ,f5
7/
10 A I
8 C
2 C
h — //
3 ,
108R F
.___..2 _
1 L 11111111 L 1 1141111 1 1111111
0C3 0C6 001 0.3 0.6 100 300 6.0
FIGURE 1. EXCHANGE RATE.AS.A FUNCTION OF CHLORIDE

A- Slope = 2.05

[3- Slope =
D- Slope =

C} Slope = 0.82

 

chlcr

ah‘{

6‘ '1
s ‘_

1.1+

The decreasing slope at high chloride is most probably
the result of the system approaching a pseudo-zero order
chloride dependence because of the gross excess present, and
should not be interpreted as lack of participation of
chloride in the exchange reaction.

The McKay plots did not all yield the anticipated linear
relationship between log(l-F) and t. At 6 fl chloride, the
plots are linear. With decreasing chloride concentration,
deviation from linearity at low (l-F) values occurs, reaching
a maximum in the region 1-2 x. From 1-0.h fl chloride, this
deviation decreases, until the McKay plots are again linear.
Typical examples are illustrated in Figures 2, 3, and h.
Half-times for exchange and rates for runs exhibiting this
phenomenon were obtained from the linear portions.

The observed curvature could be the result of several
effects. Two different Species could be involved in the
electron exchange, and the equilibrium between these species
could be kinetically slow. Alternatively, the curvature
could be the result of the formation of a non-exchanging
Species, either a hydrolyzed form or perhaps an interaction
dimer. Absorption spectra of the individual Sb(III) and
Sb(V) solutions, and the Sb(III)-Sb(V) exchange solution
in 2 M chloride were obtained one hour and 2% hours after
zero time. If hydrolysis were occurring, one would
anticipate the absorption to shift toward shorter wave-

lengths; if an interaction dimer were forming, a Shift to

‘+5

 

0.5

0.h

(l-F)

0.3

0.2 r-

 

0.1 1
0 1

FIGURE 2.

 

I [I 111 I 11 11 l

2 31+ 5678 910111213

TIMEVL HOURS
TYPICAL EXCHANGE IN 6.00 p CHLORIDE
t3 = 7.62 hours

 

(l-F)

(3.6

0.5

0.h

0.3

0.2

0.1

#6

 

 

l 1 l 1 l l l J 1 l l L I

J

 

o 51015202530351+0h550556065
W

FIGURE 3. TYPICAL EXCHANGE IN 2.00 _1_1_ CHLORIDE

t3 = 10.6 hours

 

L17

 

 

 

L
0.9 30
0.8 — b\
p

007 _ \\O

0.6 r—

0.5 e—

0.h ——
Eh

I
3 o

0.3 r—

' \
\
\

0.2 ——

C, illlllllllill

' O 20 no 60 80 100 120 IMO 160 180 200 220 Zho 260

TIME, HOURS
FIGURE 1». TYPICAL EXCHANGE IN 0.20 11 CHLORIDE

ti = 123 hours

 

#8

longer wavelengths would be expected. The Spectra, however,
exhibited absolutely no change. Runs in 0.20 and 2.00 M
chloride were made at h2.0 °C. to observe the effect of
temperature. It was necessary to assume that this temperature
change had a negligible effect in calculating the concen-
trations of the Species in the exchange solutions. The

data obtained are given in Table III, and McKay plots are
illustrated in Figures 5 and 6.

By examination of the data at the two temperatures for
the runs in 0.20 and 2.00 K chloride, it is immediately
obvious that a pseudo-Arrhenius plot of log R 1;. l/T will
yield two quite different SlOpes, with the SIOpe of the
2.00 g exchange being considerably greater. This observation
is in agreement with the more pronounced curvature of the
non-linear McKay plots at 2h.8 °C. as compared to 82.0 °C.
Apparently there are at least two mechanisms for the
exchange, and the exchanging species are functions of the
chloride concentration. In the intermediate region of
chloride concentration, the processes are competing, with
21 kinetically slow equilibrium between the exchanging

S pecies.

TABLE III

EXCHANGE AT H2.0° C.

 

 

 

, K c = 3.19, [IV] = 9.75 M, [sous] = 0. 71+ M, [3301:]
M, vgsoh] = 3. 01 M [C10 1 = (6. co - E 1'9"!) 23,
17): 1.31 x 10-3 jtsb(v11= 1.31 x 10- 3.M

Ella t‘; R

9; (hours) (moles/liter-hour)
2.00 2.00 2.28 x 10"1+
2.00 2.22 2.0» x 10'1+
0.20 53.u 8.50 x 10"6

c.2o 58.2 7.80 x 10'6

 

‘50

 

0.8

0.7

0.6

1 I I I

//

0.5

0.1”—

O.2 P- O

 

I J l l 1 1 J l L l l
3 1+ 5 6 7 8 9 10 11 12 13
TIME, nouns

FIGURE 5. EXCHANGE IN 2.00 M CHLORIDE AT 1+2.0° c.

l

O 1

m L—

0.1

t% = 2.00 hours

 

l-F

51

 

 

 

 

0.9 -
0.8%
0. I
7% ‘
\CL.
c.6— “ \
C)‘\\\\
O\
C°5‘—' \13\\\CL\\\\\\\\\\
I. <3
C.h C)
(D
003?—
0.2——
011.11111111111l11
’0 510152025303511011550556065
TIME, HOURS
FIGURE 6. EXCHANGE IN 0.20 .11 CHLORIDE AT 112.0° c.

t% = 58.2 hours

\fl
[‘0

2. The De endence of Exchange Rate on the Concentration of
Sb(IIIS and Sb(V)

The dependence of the exchange rate on the concentrations
of Sb(III) and Sb(V) was determined at 6.00 and 0.20 M
chloride. The study of the exchange in 6.CO fl chloride was
chronologically the initial investigation performed, and
the concentrations of the solution species and the ionic
strength are somewhat different than those employed in the
bulk of this work. However, at 6.CO M chloride, sulfate
does not influence the exchange, and the effect of ionic
strength is negligible (note runs at constant concentration
and varying ionic strength in Tables VIII and X). The
only important variation is that due to hydrogen ion, but
at 10 M_(H+), a difference of C.25 in molarity should not
produce an important change in mechanism.

In 6.00 M chloride, the orders with respect to Sb(III)
and Sb(V) were found to be 1-0“-:.10 and C.97':;1o. In
0.20 g chloride, the Sb(III) dependence was still unity,

a value of 1.01 1,09 being derived from the kinetic data,
but Sb(V), with an observed order of 0.76 1,08 , displayed
a significant deviation. Kinetic results are presented

in Tables IV and V, while the log-log plots are illustrated

in Figures 7 and 8.

DEPENDENCE CF EXCHANGE RATE ON THE CONCENTRATION OF Sb(III)

11- 12 .0, K

T ABLE IV

AND Sb(V) IN 6 .00.fl CHLORIDE

£111.14 6") °111’=

 

 

 

1g; §:10§$:g-:E €561,318: = 0. 852‘} M, [1.1301,],
@b(111fl [sb(vj tt R/ab
M 14 (hours) 1119th lit r
éiter-hom) Gnole-hour

1.31x10'3 0.6h5x10'3 11.5 2.60x10'5 30.8
1.3lx10’3 1.29xlO’3 10.0 n.50x10*5 26.7
1.31::10"3 1.29x10'3 10. h.h2x10'5 26.1
1.31x10'3 1.9hx10'3 8.85 8.1hx10‘5 32.1
1.31x10'3 2.58x10’3 6.h8 9.29x10'5 27.5
c.655x10'3 1.29x10'3 12.7 2.37x10‘5 28.1
1.97x10'3 1.29x10‘3 6.9M 7.78x10'5 30.7
2.62x10'3 1.29xlO'3 6.27 9.552(10‘”5 28.3

TABLE V

5%

DEPENDENCE OF EXCHANGE RATE ON THE CONCENTRATION OF Sb(III)

AND Sb(V) IN 0.20 M CHLORIDE

 

 

 

MP;0:%-5; 25713.1 $501,] ==3?6Z5_M¥’ [ggfi : 95.8: {21’
§b(IIIfl @b(vj ti V R
g 5 (hours) moles

finer-hog
0.655x10‘3 1.29x10'3 1MB 2.03::10"6
1.31x10‘3(a) 1.30x10‘3 118 3.82::10"6
1.97x10'3 1.29x10'3 8u.1 6.1122(10"6
2.62x10‘3 1.29::10‘3 73.7 8.13::10-6
3.93x10‘3 1.29::10‘3 56.9 1.18x10'5
6.55x10’3 1.29x10'3 35.7 2.09x10’5
1.3hx10'3 0.6u5x10'3 120 2.51::10-6
l.3lxlO"3 l.9‘+xlO"3 95.5 5.67x10'6
1.31x10'3 2.58::10"3 9h.3 6.39::10"6
1.31x10'3 0.u19x10‘3 135 1.611x10'6
1.31x10’3 3.78x10‘3 78.2 8.62::10’6
1.31::10'3 n.97x10'3 63.1 1.1hx10'5

(a) Average of 11 runs (see Table X)

 

 

 

 

 

 

 

1
i
1
E5 L. <5 ,
9: 10 i
I 91— 1
1
E it /’ 1
t-J .
co 6“ I
g 5‘—
2: 1 B
1+_
3—
106R
2 e 1
//
1
1L__L....-.L_.1__-111| 1 1 1 1 1 1 1
0.3 0.6 1.0 2.0 3.0 9.0 6.

Sb(III) ! x 10

 

FIGURE 7. EXCHANGE RATE.AS.A FUNCTION OF Sb(III)

- Qlope = 1.0% - Slope = 1.01
A [:11 = 6.00 B Er] = 0.20

56

 

 

 

 

 

 

_-_L.L---._-.-.r..-._1,1L111L11111- -1: _-._ .1_T--_.1-L.1

00/876 5 14. 3

1 5m

2 qmac/876.51....

 

EgufiquWmmqox

 

 

LlLll

I

 

1.0

0.6

(3.3

EXCHANGE RATE AS A FUNCTION OF Sb(V)

FIGURE 8.

57

3 - Variation of Exchange Rate with Sulfate Ion Concentration

The effect of sulfate ion was observed in the range
C -20 - 1.25 y; in solutions containing 0.20 E; chloride.
While Sb(III), Sb(V) and hydrogen ion concentrations were
held constant, it was necessary to permit ionic strength
and bisulfate ion concentration to vary. Kinetic data
obtained in C.20 fl chloride are shown in Table VI, while
the log-10g plot of rate y_s_. sulfate concentration is given
in Figure 9.

In 0.20 M chloride, the exchange Iate exhibits a
parabolic dependence on sulfate cc-ncentration. with the
maximum occurring in the region 0.6 - 0.7 L1 sulfate. The
cu.rve is approximately symmetrical, and an estimation of
of slope yields 0.7 - 0.9 before the maximum, and minus
0 -7 - 0.9 beyond the maximum. [apparently the region
Q -6 - 0.7 113 sulfate is the most favorable for the formation
Of the exchanging species. The considerable experimental
Scatter in the region of the maximum is probably the
reSult of significant rate changes due to small errors in
the preparation of the exchanging solutions.

In 6.00 3;: chloride the rate of exchange is independent
of sulfate concentration as would be expected in the
pI‘Eésence of such a large excess of chloride. Kinetic

reS'ults in 6.00 M chloride are given in Table VII.

58

TABLE VI

DEPENDENCE OF MCFANGE RATE ON SULFATE ION CONCENTRATION IN
0.20 M CHLORIDE

 

 

 

- = 9.75 1.4., Ell-J 0. 20_,Esb(1113= 1.31 x 10-3 15,
512W] = 1.30 x 10 "=3 M
r so - H30 11 C10

iter-hou
10.1 3,21. 0.20 0.60 0.15 8.70 220 2.061110?
10.1 “21+ 0.25 0.75 0.10 8.90 221 2 .c5x10'
10.1 3.2M 0.31 0.9M 0.011 8.03 181 2. 50x10 _6
10.5 3.19 0.37(a)1.13 0.38 8.06 152 2.96x10
10 .5 3.19 0.37 1.13 0.38 8.06 150 3. 01x10 ‘2
10.5 3.19 0. I. 1.36 0.31 7.62 11+6 3.10x10‘
10.5 3.19 0.52(a)1.58 0.23 7.16 123 3.66x10'2
10.5 3.19 0.52 1.58 0.23 7.16 135 3.35x10‘
10.5 3.19 0.57 1.7% 0.18 6.86 107 1+.2 1:10-:
10.5 3019 C062 1.8 0013 6056 970” LT06 110-
10 .5 3.19 0.68 2.07 0.07 6.19 118 3.801110“:
10.5 3019 0071+(b)2c27 "" 5.80 118 3.82110-
10 .7 3.1L. 0.83 2.57 0.12 5.9% 111 11.061110?
10 .7 301” 0093 2.87 "" L"082 121+ 3.651(10-
11.0 3.02 1.06 3.141 0.20 11.19 136 3. x10 6
11.(‘ 3.02 1.111 3.66 0.11 3.72 127, 3. 56x10“ 6
11.0 3.02 1.20 .88 0.05 3.32 156 2.90x10'2
11.0. 3.02 1.25 .05 -- 3.00 181 2.50x10’

(8) [Sb(vfl = 1.29 x 10‘3M

(b) Average of 11 runs (see Table X)

lC

MOLES TIER-HOUR

1

 

 

 

 

59

 

 

 

0
I <3
0 C) C)
C><3
C) (D C)

I C) C)
3 C)
I 8 o
' 0 0
g}
_. - L I I I I I I I I I

0.3 0.h 0.5 0.6 0.7 0.8 1.0 1.2

MOLAR 501+—

FIGURE 9. EXCHANGE RATE AS A FUNCTION OF SULFKTE

 

()\
1’.)

TABLE VII

DEPENDENCE CF EXCHANGE RATE 011 SULFATE ION CONCENTRATION IN
6.00 111, CHLCRIDE

 

 

11*] = 9.75 .11, [01'] = 6.00 12, [Sb(III)] = 1-31 X 10-3 14’
Sb(v] = 1.30 x 10‘3 his
K 801.: mo - MN] 10 R
2“ 2c [21' ] bf] [14 EM J (hours) moles
liter-Hour

 

10.1 3.2% 0.20 0.60 0.15 2.70 7.02 6.41600’5
10.5 3.19 0.52 1.58 0.23 1.36 7.65 5.91::10’5
10.5 3.19 0.71. 2.27 -- -- 7.62 5.93x10’5

 

TABLE VIII

DEPENDENCE OF EXCHANGE RATE CN HYDROGEN ICN CONCENTRATION

IN 6.CO 14 CHLORIDE
Eb’tvn

c .70 103311100 5, [Sb(III)] = 1.31 x 10-3 14,
1.30 x 10
)u K2c [11*] [11801;] [11+] [0100-] 1:45 R
M M M (hours)
{iter-houA

1c.5 3.19 8.00 1.86 1.76 03.2 8.06 5.61x10'5
10.5 3.19 8.50 1.98 1.26 0.30 7.66 5.90x10‘5

 

 

 

 

10 0 S 3019 9 075 2 .27 -" -- 7'62 5'93X10-5
11.0 3.02 10.25 2.09 -- -- 8.96 5.05on"5
11.7 2.60 11.00 3.13 -- 0.39 10.1 L+J+8x10"5

61

h-- Variation of Exchange Rate with Hydrogen Ion Concentration
The magnitude of the rate of exchange between Sb(III)
and Sb(V) was determined for hydrogen ion concentrations
of 8 - 11 kg in both 0.20 and 6.00 1“; chloride. In order to
effect the desired changes in hydrogen ion, it was necessary
to permit the ionic strength and bisulfate ion concentrations
to vary. These data are summarized in Tables VIII and IX.
The log-log plot of g yidl-N) for solutions containing
0 -20 If. chloride (Figure 10) displays a sharp maximum at
about 9 M hydrogen ion. Statistical evaluation of the data
yielded a slepe of 9.0 in the region 8- - 9 13; hydrogen ion,
and a negative 5.5 slope in the hydrogen ion range of
9 - 11 E. In solutions containing 6 M chloride, the rate
of exchange is not as sensitive to hydrogen ion variation,
but an apparent maximum exists at approximately the same

concentration as in 0.20 M chloride (Figure 10).

C . Spggtzgggopgg Stugigg
A comprehensive SpectrOSCOpic investigation of Sb(III)

and Sb(V) solutions was not conducted, but some spectral
data were recorded. In aqueous sulfuric acid, Sb(III) and
Sb(V) exhibit the same type of absorption spectra as have
been reported for hydrochloric acid solutions. No peaks
are observed in the accessible spectral region; absorption
1ncreases steadily with decreasing wave length. The

Position of the absorption band is a function of both

L HOLES HEB-HOUR

 

 

62

 

 

 

 

10~— ~- "- --
9.-
8—
7+—
6" e e

e
5*- G

e
no.
G
\O

3 *— O

A B

O \
2 e j \l

o \

z

/

O.
“I liLLlllJlllHllj
5 6 7 8 9 10 11 12 1h 16 18
MOLAR H+
FIGURE 10. EXCHANGE RATE AS A FUNCTION OF HYDROGEN ION
A- Slope = 9.0 o- 0.20 21 01', R x 10?
B- Slope = -5.5 e- 6.00 32 Cl', R x 10

63

TABLE IX

DEPENDENCE OF EXCPANGE RATE 0N HYDROGEN ICN CONCENTRATION
IN 0.20 33 CHLORIDE

 

 

 

Essfifzjzfc‘f’; tx’x1[8}§]f 0.20 33, [Sb(III)] = 1.31 x 10-3 M,
)u Kgc [H'] [fisou'] [L13 [0101f] t’5 R
E M .M E (hours) 22l§§

éiter-hour
9.0 3.18 8.00 1.86 0.26 Ln72 255 1.77::10‘6
9.0 3.18 .25 1.92 -- 9.65 201 2.25::10"6
9.5 3.29 8.50 1.91:. C.26 5.1M 131+ 3.37::10'6
10.1 3.21. 8.75 2.00 0.61 5.68 91.7 1+.93x10“6
10.1 3.2% ,.00 2.06 0.36 5.62 87.7 5.16::10‘6
10.1 3.2% 9.00 2.06 .36 5.62 91.3 L+.97x10"6
10.1 3.2% 9.25 2.11 0.11 5.66 11h 3.97::10'6
10.5 3.19 9.25 2.15 0.51 5.93 118 3.83::10"6
10.5 3.19 9.50 2.20 0.26 5.88 12h 3.65x10'6
10.5 3.19 9.75* 2.27 -- .80 118 3.82::10’6
10.7 3.1% 10.00 2.36 -- 5.96 191 3.21::10'6
11.0 3.02 10.25 2.51 —- 6.06 155 2.922x10‘6
11.7 2.6011.00 3.13 -- 6.19 367 1.23::10'6

* Average of 11 runs (see Table X)

61¢

antimony and sulfuric acid concentrations; with decreasing
acid or antimony, the absorption is shifted toward shorter
wave lengths. Typical spectra in aqueous sulfuric acid are
depicted in Figures 11 and 12. The effect of variation in
sulfuric acid concentration at constant wavelength is
indicated in Figure 13. Antimony(III) solutions obeyed
Beer's law for all acid concentrations and wavelengths
observed (Figure 1%), but antimony(V) displays pronounced
deviations (Figure 15). Continuous variation experiments
with Sb(III) and Sb(V) were performed in 12.7 and l1.00 £51
sulfuric acid, but no interaction absorption was discovered.

Figure 16 illustrates the spectra that were obtained
with solutions containing 0.20 z; chloride, simulating those
utilized in the kinetic work. The presence of chloride
Shifts both the Sb(III) and Sb(V) absorption to longer
Wave lengths, but a much more drastic effect is observed
with Sb(V).

To show any interaction between sulfate ion and Sb(III)
and Sb(V), experiments were performed in which sulfate
concentration was varied while hydrogen ion was maintained
Constant at 9.75 g. The result for Sb(III) absorbsnce at
fixed wavelengths y_§_. sulfate ion is depicted in Figure 17.
A similar experiment for Sb(V) could not be successfully
completed. Spectra were recorded approximately 18 hours
81'ter the preparation of the solutions, and in this time
11'l‘lzerval precipitation occurred from 0.20, O.‘+’+, and C.7’+ I:

65

sulfate. The amount of precipitate observed varied from a

heavy deposit in 0.20 M sulfate, to a faint opalescence in

0.7% g sulfate. The complete Sb(V) spectra for sulfate

concentrations of 1.06 and 1.25 M are illustrated in
Figure 18.
Similar experiments were performed in solutions

containing 0.20 1*: chloride, where no difficulty with Sb(V)

precipitation was experienced. The resulting spectra are

portrayed in Figures 19, 20, and 21.
While the spectroscopic data do not establish the

nature of the species present, qualitative observations

are possible. It may be presumed that in aqueous sulfuric
acid, Sb(V) is present as an equilibrium mixture of sulfate

complexes. Sb(V) spectra are markedly dependent on sulfuric

acid concentration, and the behavior of Sb(V) at constant
h)Vclr-ogen ion with the variation of sulfate indicates
Sulfate complexing and not only anionic polymerization.
In 0.20 M chloride, decreasing absorption with increasing
Sulfate concentration reveals a competition between chloride
and sulfate, and the Sb(V) solution species are presumably
an equilibrium mixture of complexes of sulfate and Chloride.
Sb(III) apparently forms a sulfato complex, but the

e<hailibria involved are probably not as complicated as those

1.01‘ Sb(V). Beer's law is followed in aqueous sulfuric acid,

which indicates that the number of species present is limited.

It is interesting to note the apparent maximum in absorption

66

at approximately 0.6 g sulfate in the variation of absorb-
ance with sulfate at constant hydrogen ion (Figure 17).
This is the region of the maximum exchange rate in the
kinetic study of the effect of sulfate, and indicates that
the exchanging species for Sb(III) may be a sulfato complex.

67

23:5 m TS a oo.m -m

   
    

 

93m m TS a oo.m -<

0+.N
E..._: !

HmDhHDm m 00.: 2H «mammm EROH>§BQD 2: "%5on

0mm 0mm

00. O

 

|e

10H.O

lON.O

I.om.0

 

\84

 

RON V880 SEW

68

323% m. TS on aim .0 :96 m. TS x «in ..<

QHU< UHmDmHDm fl «ZNH 2H éaomam EAOH><mHHD .NH "$5on

mm 2H maozmqm>¢3

N Om O N
Ninaufikiomm-Julnvublwi +3-10%.“ - .i..0 .wzl 3m m m 00.0

)i/ 1 a S _

 

IOHoO

ION.O

IOJ.O

[Om.0

 

100.0

i230

.[Ow.O

 

 

Inll’lll’
fi‘lzL K

LON V830 88V

A BS ORBA NCY

 

 

1.00

CO9O_

 

0.70 '—

0.60}—

6.5m-

c.30r- /

0.20 L B

,,///””//£}//z

 

 

 

1111111111|11
0.
0° 678910111213

MOLAR H2501,
FIGURE 13. ANTIMONY ABSORBANCE AS A FUNCTION OF
SULFURIC ACID

A- 6.95 x 10"3 g Sb(III) B- 6.1m x 10-3 g Sb(V)
at 21+2 mu at 228 mu

 

0090 _

 

A BS ORBA NCY

 

 

 

 

_ J
9.0 5.0 6.0
MOLAR Sb(III) x 103
FIGURE 11+. ABSORBANCY AS A FUNCTION OF Sb(III)
A- 2n0 mm 12.7 M so — 210 mp l+.00 31 so C- 215 mu
12.7 21 H2S01+ D- 21+?mph [2.00 M HZSOn E- 25g2mnl: 12.7 .13 H2S01+
F- 250 mm “.00 2:1. H2301.

111-1111 _ f

ABSORBANCY

 

0.90

0.80

C.70n—

0.60-

0.50

0.h0

0.30

0.20

0.10

0.00

 

 

 

I L .L
1.0 2.0 3.0 h.0 5.0 6 0
ggpAa Sb(V) x 103

 

FIGURE 15. ABSORBANCY AS A FUNCTION OF Sb(V)

A 218 mp, 1+. 00 M H 2301, B- 230 mp, 12. 7 M 32501,
C" 230 m1, I"’QOO H H28 01+

21

 

72

9me m -S a Sm;
AHHvam z m

ow.o u A-Hov .ow.m u A-:oaov .em.m u humommv .mu.o u Ausomv.mm.mun+mv
«Sm: zSBgom moimsm 2H éSmmm 205.22 .S %5on
.045 maozmgmix
06m o:m 0mm 0mm cam 00m 0mm
1 _ J _ _

 

 

 

..S a $4 -0 :03 2 TS a «Tm .0 330nm 1». TS x mm.m -<

OH.O

ON.O

0m.o

91.0

8.0

00.0

05.0

ow.o

 

1100.0

84

 

L

KONVHHOSHV

ABSORBA NCY

 

 

 

 

 

 

 

 

O 090”—
0.80L A
/3/”«-\0
0070; 'r;
0060i—
? B Q
0050— //7/\3 _
0.408— \\\\\\\\\\\w3
. C
)
0030‘ / ‘\ O
o \ /
C)
0.20-
Cf///,,id—C%——£2__‘__~C}‘\‘\‘~§‘fi‘-Cffl”//)D
0.10*‘ E
’»“*"C*—““-———J\__
O/ V 0/0
I l | 1 I l l | l | l l l “J
0‘00 0.1 0.3 0.5 0.7 0.9 1.1 1.3

MOLAR SOL,=

 

FIGURE 17. Sb(III) ABSORBANCE AS A FUNCTION OF SULFATE

(11*) = 9.75 11 Sb(III) = 2.62 x 10-3 M

A-23leu B- 235nm C- 2110:1111 D- 216m}: E-250m11

 

7h

O0N

 

 

2H mewzw§>¢3
00m

Gum

«mom: 2 mo.

OH on NO. m u 350.0
éewmmmo 230.0 20 mafimgm mo

000.

0mm

Hum.

"Jomm
: n
how

3m

m
0.0
Em

H -41
u +m
mma

0mm

.mH mmDon

 

 

.H

r

0

_

_

_

_

Jam oo.o

 

10.70

ION.O

om.o

9.

RON V880 38V

0m.o

5?

00.0

ow.o

1100.0

IOO.H

 

 

 

 

 

 

 

 

 

 

 

0.80i—
0070b—
[3
0.600
a E
20050—
E”:
5 C
88
¢Oe)+0_
0.30~ D
I //,,—ow fio/O
0.200
,L E
0.10— Q/‘O'flf U 3
0.00I111111111111J
0.1 0.3 0.5 0.7 0.9 1.0 1.3

. MOLAR 50f
FIGURE 19. Sb(III) ABSORBANCE AS A FUNCTION OF SULFATE IN
0.20 1;; CHLORIDE 11* = 9.75 h. Sb(III) = 2.62x10'3 I“;

A- 285 mp B- 290 mp C- 295 mp D- 300 m1 E- 310 mp

0.80F-

0.70-

 

ABSORBA NCY

 

0.305’

0.20—

 

0.00

76

(W

 

11111111111I1
0.1 0.3 0.5 0.7 0.9 1.0 - 1.3

MOLAR SO '
FIGURE 20. Sb(V) ABSORBANCY AS A FUNCTION OF SULFKTE IN

0.20 11 CHLORIDE 11* = 9.75 g, Sb(V) = 2.62x10'3 :2
A- 330m! 8- 310011111 C- 360m}:

77

 

0.90 r-

0070 —

C.60‘—

A B8 CREE NCY

 

 

 

 

0.50
OAK)? CNN
\
o.30~
C
0.20!”
0 D
11 l I J I 13 [J 11 I
0‘00 0.1 0.3 0.5 0.7 0.9 1.0= 1.3
MOLAR son

 

FIGURE 21. Sb(III)-(V) ABSORBANCY AS A FUNCTION OF SULFATE IN

0.20 y, CHLORIDE H" = 9.75 h, Sb(III) = 1.3131181?» 14

A- 320 mu [3- 330 mu C- 310 mu Sb(V) = 1.3lx10 1;;
D- 360 mu

‘3
C0

D. Disgussion of Errors

The sources of error in the rate of exchange as
determined by these experiments may be classified as follows:
1. Preparation and standardization of stock solutions.

2. Preparation of solutions for exchange runs.

3. Conduct of kinetic eXperiments, separation of antimony
oxidation states, and mounting of samples.

h. Radiochemical assay.

It was necessary to prepare and standardize stock
solutions of sulfuric, perchloric, and hydrochloric acid,
lithium chloride, antimony(III), and antimony(V). For each
run five to seven components were measured or weighed into
each of two flasks. All these operations were subject to
the normal errors of quantitative procedures. Errors
introduced by temperature variation and sampling time
inaccuracy were insignificant because the temperature of the
exchanging solutions was easily maintained within 1 0.02 °C.,
and a generous estimate ofli 15 seconds in sampling time
may be compared to exchange half-times of 50 - 100 hours.
The shortest half-time observed was two hours.

In the separation method employed, both positive and
negative errors are possible, either from incomplete extrac-
tion of Sb(III), or possible contamination of the chloroform
phase with Sb(V). This error is minimized by the fact that
all the points established for a run were used to evaluate

a statistical slope from which the rate of exchange was

calculated. The accurate determination of equilibrium
activity at infinite time is most critical. As described
previously, three samples were taken from each run to
establish this quantity. These values, in general, agreed
within the limits of the radioassay. Securing of a minimum
of 10,000 counts in this process should limit these errors
to 1%, and indeed reproducibility was found to be within
these limits.

With all these potential sources of error, it is
difficult to assess the contribution of each and sum them
to yield a meaningful approximation of the error in the
determined rate of exchange. An estimation of the precision
of this work is possible, however, because of the repeated
determination of the rate of exchange under standard
conditions, for sample solutions with the following
concentrations: [HI] = 9.75 fl, [8013 = 0.7% g, fiiSOgj =
2.27 y, Enj = 0.2011, Eloy] = 5.80 3;, [Sb(IIIj =
1.31 x 10"3 14, and [Sb(vj = 1.30 x 10‘3 11.

This rate of exchange was determined eleven times
during the course of this study. USually each set of
kinetic runs that were prepared included a "standard sample",
which served to monitor the quality of the stock solutions
and the correctness of the experimental procedures. Results
obtained are summarized in Table X.

Calculation of the standard deviationcj', where:

0'2 =

1 n _»2
I1- §CRi ~R)

)713105 a value for the rate of:

R = (3.82 1 0.19) x 10'6

moles/liter-hour

(‘D
’7‘)

A precision of the same order would be anticipated

for all the exchange runs performed.

 

 

 

 

TAB

LEX

RATE OF EXCHANGE OF "STANDARD" RUN

 

 

H+J = 9.75 .12 11 = 10.5 K = 3.19 [so =] = 0,71. M 1130 j
E 2-27 II. 0113 = 0.20 2,1, 10 " £58013, [Sb(IIIfi = h
1.31 x 1 ' 11, [Sb(V)] = 1.30 ‘x‘ 10-3 14

t? (hours) R ( moles\
IICEEifiafir
123 3.66 x 10':
115 3095 x 10-
118 3.82 x 10'6
121 3.7% x 10‘
-6
115’ (a) 3.93 x 10
112 (b) n.0u x 10"6
111 n.66 x lo-g
121 3.7% x 10'
122 3.69 x lC'g
123 3.68 x 10'
122. 3.21 x 10'6
éiverage: 118 3.82 x 10'6
(a) m = 10.7 K = 3.1%
(b) n = 11.0: Kg: = 3.02

 

 

 

VI. DISCUSSION

While some study has been made of the chloro-species
<1f antimony, no previous work has been reported in aqueous
sulfuric or in hydrochloric — sulfuric mixtures. Because
cxf the complex equilibria which exist in these media, any
<11scussion of exchange mechanisms must remain qualitative
umitil a more complete evaluation of antimony species is
available.

No exchange was observed in aqueous sulfuric acid.

Some deductions as to the nature of the antimony species
(Hid for the absence of exchange can be made by interpretation
of the spectra recorded in this medium. Observations of

the Spectra of antimony(III) seem to indicate that some
smzlfate complexing does take place. In the plot of Sb(III)
absorbence at fixed wavelength.ys, sulfuric acid concentration,
a shallow minimum is observed at 6 - 7 fl HéSOg. This is the
region of maximum sulfate ion concentration from the data

of Smith (65). The plot of Sb(III) absorbsnce at 9.75 y

EH? ;gg. [Sohf] also indicates interaction between sulfate
ion and antimony(III). Antimony(III) species may be postu-
lated as Sb0+, SbSOgI, and Sb(80g)§. Solid phases obtained
from antimony solutions in sulfuric acid have been shown

to be (Sb0)2SOg and Sb2(50h)3.

Antimony(V) absorption is even more sensitive to

sulfuric acid concentration. With SbClé', Neumann (32)
observed that as chloride ligands are replaced by hydroxo
groups, the wavelength of the sharp increase in absorption
is displaced toward the ultraviolet. A similar diSplacement
is obtained for Sb(V) as sulfuric acid concentration is
<diminished. It is logical, therefore, to postulate species
ranging from Sb(SOg)3' at high acid concentrations, to
Sb(OH)6' at low concentrations.

If these conclusions as to the nature of the antimony
species in sulfuric acid are correct, it is difficult to

explain the lack of exchange. Exchange mechanisms such as:

‘—

soh son =
Sb(SOh)2' + Sb(SOg)3’ = ‘Sb-SOg-Sb/
sog’ \sou
°r‘ so sou so“

[0=ébl.]-+ [SOg-S'b-SOLJ " = [0=Sb-SCq-S|b=0] '-'

are particularly attractive because of symmetry' and a
minimum subsequent rearrangement in coordination Spheres.
{The conclusion is forced that the system is not as simple
as wishful thinking fancies it to be. For such high
oxidation states, anionic polymerization is a well known
phenomenon. Souchay and Peschanski (23) reported the
principal Sb(V) Species in weak, weakly complexing acid
Inedia of pH 2.5 - 0.9 to be RS66017‘3. Undoubtedly, Sb(V)
in.sulfuric acid also exists as a polymeric species. In

‘the preparation of Sb(V) by the oxidation of Sb(III) with

"peroxy acid", a solid phase separates as the oxidizing
medium is heated, and dissolves slowly on prolonged digestion.
This is presumably an insoluble antimonic acid which dis-

solves as sulfato complexes form. If Sb(V) exists only as

a dimer such as:

SO /0\ /SO)+
50an MRS

no exchange would be expected, and the true species are

probably much larger than this.
In aqueous sulfuric acid solutions containing 6.00 g
chloride, an electron exchange reaction did occur between

Sb(III) and Sb(V). With [11+] constant at 10.00 u, an

empirical rate law:
R = k [Sb(III)] 1'01“ [0600] 0'97

can be written. Sulfate ion concentration was found to
have no effect on the rate, and a chloride term is omitted
from the rate expression because at this extremely high
ratio of chloride to antimony, the system is approaching a
DS etido-zero order dependence on chloride, and the observed
Slope of 0.28 obtained from the log-log plot of R 1;. [Cl']
in the region 1.50 - 6.00 N chloride is meaningless. This
result is in agreement with that of Cheek (11), who found

a first order Sb(III) and Sb(V) dependence in 9 ' 12 39-
hydI‘Ochloric acid. In this medium, the exchange apparently

takes place exclusively betwem chloro complexes of antimony.
The exchange rate approaches a maximum in the region

9 - 10 11 hydrogen ion. At [H] = 10.00, according to

DIeumann (12, 32, 33), Sb(V) should be present almost entirely

as SbCl6', and his postulation of SbCl3 as the exchanging

s pecies of Sb(III) explains the effect of hydrogen ion.

Increasing hydrogen ion beyond the observed maximum at

[H +]= 9, favors the formation of SbCln', a non-exchanging

species, as the activity of HCl increases. The exchange

intermediates that Ueumann proposed:

/Cl - MCI '-
Cl Sb /SbCl and c1 SbE Cl-SbCl
‘* Cl/ 3 3 \/C1 3

seem reasonable for this system also.

In aqueous sulfuric acid containing 0.20 .15 Chloride,
rate data indicate that both chloride and sulfate participate
in the electron exchange reaction. A standard system of
[Hf] = 9. 75 M, 60;] = 0.79 n, Esog‘] = 2.27 14,, [0101;]:
5- 80M ,[sMIIIj = 1.31 x 10'3 1;, and [Sb(V)] = 1.30 x 1031/;
was ad0pted, and [11*] , [80,3], Er] , [Sb(III)] , and Ebw]

ind ependently varied .

At constant hydrogen ion'and sulfate concentration, the

f0110wing empirical rate law can be written:
R = k EbUIIfl 1.01 EMW] 0.76 £31.] 2.0%

for the concentration range 0.025 - 0-20 .M chloride. The

(‘0
U1

pr0per exponent of the chloride term is debatable because
the points at C.20 E, chloride are in a region of changing
lepe in the log-log plot, and also fit the lepe of 1.1+l
determined for the region 0.15 - 0.60 2’; chloride. The true
order is undoubtedly some intermediate value.

Sulfate and hydrogen ion dependence are difficult to
place in an empirical rate expression since both exhibit a
maximum. The sulfate maximum occurs at 0.6 - 0.7 y; (80):),
and the observed slopes are approximately 1 (C.7 - 0.9).
The hydrogen ion maximum occurs at about 9 y (W), with a

slope in the log-log plot of 9.0 in the range 8 - 9 )1, and
a negative 5.5 slope in the range 9 - 11 g. In this system,
antimony species exist in equilibria involving chloride,
sulfate, and hydrogen ion. Spectral data indicate that both
Sb(III) and Sb(V) are present as chloro-sulfato complexes,
and the order with respect to any particular species is
Probably a parameter determined by the concentrations of
each of the other Species.

If the assumption is made that the neutral molecule
s—‘bClSOL+ is the exchanging form of Sb(III), the effect of
hYdrogen ion may be interpreted as in the hydrochloric acid
System. Increasing hydrogen ion will increase the concentra-
tion of this species compared to such forms as Sb0+, SbSOLS,
and SbCl++. However, as hydrogen ion continues to increase,
anionic species such as SbClu', Sb(SOh)2" and SbClESOu"

Should result. Furthermore, beyond the maximum, anionic

86

polymerization of Sb(V) may be favored, as well as proton-
ation of potential bridging chloro and sulfato ligands.

The initial increase in rate with increasing sulfate
may be the result of the formation of SbClSOq, the presumed
antimony(III) exchanging species. Increasing sulfate beyond
the maximum may favor polymerization of Sb(V), the form-
ation of anionic Sb(III) species, or may result in the
prevention of necessary chloro-bridges in the activated
complex.

While both sulfate and chloride are involved in the
transition state, it is difficult to assess their relative

contribution as bridging groups in the exchange. The
initiation of exchange by small amounts of chloride is
probably the result of its effect on the nature of the Sb(V)
species, where the initial action of chloride may be to
decompose the Sb(V) sulfato polymers. The fractional order
observed for Sb(V) indicates the presence of at least two
Sb (V) species, one of which does not participate in the
exchange. Because of the lack of accurate knowledge
concerning the nature of the ions in solution, it seems
rather futile to postulate the mechanism of the exchange
I'eaCBtion in 0.20 15 chloride. The existence of two indepen-
dent mechanisms, one operative at high chloride concentra-
tions and the other at low chloride, is confirmed by the
phenomenon of non-linear McKay plots observed in the

intermediate region of chloride concentration. If this

87

11c1n-linearity were the result of the slow formation kinetics
of the same exchanging chloro species at all levels of
(:1110ride concentration, it would be expected that the
(:11rvature in the McKay plots would be an inverse function
()1? chloride, and not proceed through a maximum in the
xrj.cinity of 2.00 E chloride.

More work is needed before this system can be properly

evaluated. Ion migration studies to determine the anionic

0r cationic nature of the species are certainly indicated,
as well as dialysis measurements to determine the relative
ionic weights if a resistant membrane could be found. A
detailed spectroscopic examination of these systems including

study of the effect of the independent variation of
Probably the most effective

a
hydrogen ion would be useful.

tool would be a comprehensive phase study, with careful

analysis of the solid phases, for the systems Sb(III) - HCl -

5230)... and Sb(V) - HCl - H2801, .

VII. SUMRARY

The kinetics of the exchange reaction between Sb(III)
and Sb(V) was studied in aqueous sulfuric acid, and in
aqueous sulfuric acid systems containing added chloride ion.

No exchange was observed in aqueous sulfuric acid, but the
addition of chloride initiated exchange, and the concentration
of chloride had a significant effect on the observed rate.

In addition to a study of the influence of chloride concen-
tration, experiments were performed in which the effect of
independent variation in the concentrations of antimony(III),
antimony(V), sulfate, and hydrogen ion was determined at

two levels of chloride concentration, 6.00 M and 0.20 M.
Supplementary spectrophotometric examinations of antimony(III)
and antimony(V) were also performed.

In 6.00 E chloride, it was found that the reaction was
first order with respect to antimony(III) and antimony(V),
that sulfate ion has no effect, and that the dependence of
exchange rate exhibits a maximum at approximately 9 M
hydrogen ion. The exchange mechanism is apparently identical
with that observed previously in hydrochloric acid solutions.

In 0.20 x chloride, while the rate maintains a unit
dependence with respect to antimony(III), the reaction
exhibits a fractional order of 0.76 with respect to anti-
mony(V). At this level of chloride concentration, the rate

of exchange is approximately second order with respect to

C 1
\O

Chloride, but undergoes a sharp maximum at approximately

9 fl hydrogen ion and a similar, although much less pronounced

maximum at 0.60 E sulfate. The two antimony oxidation states

are apparently involved in complex equilibria with chloride,

sulfate, and hydrogen ions. Both chloride and sulfate are

involved in the activated complex, although the relative
:importance of chloro or sulfato bridging is difficult to

sassess. While some qualitative observations as to mechanism

<san.be made, a quantitative evaluation must await a more

accurate knowledge of the nature of the solution Species

311d their equilibrium relationships.

\0
(’1

VIII. LITTRATURE CITED

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and Young, T. F., Record Chem. Progress, lg 81 (1951)

Maianville, L. F., Fh.D. Thesis, University of Chicago,
19 9

Young, T. F., and Blatz, L. A., Chem. Revs., E&, 98 (1999)

Davidson N., and Sullivan, J. H., J. Am. Chem. Soc.,
21, 739 21939)

APPENDIX
ORIGINAL KINETIC DATA

\0
4—1

ORIGINAL DATA FRO!“ TABLE II

 

 

 

 

 

(page 92)
0/8 (l-F) t(hrs.)

1.31 x 10‘3 L Sb(III) 2.95 0.916 87
1.29 x 10-3 g Sb(V) 3.79 0.892 00
,p = 10.5 .96 0.858 1208
9.73 M H* 6.23 0.819 1611
0.7 5 so = 3u.35 --- oo
2.27 3 H58 -
5.975 E C134“
ti = 7,522 hrs.
1.31 x 10'? m Sb(III) h.78 c.86h 200
1.29 x 10‘3 E Sb(V) 6.81 0.807 388
9.75 m H _ 10.95 0.703 800
0.7% 3 so ’¢ 11.32 0.679 995
2.27 5 net. 13.66 0.612 1208
5.95 5 C19”- 16.3% 0.536 1928
0.05 g 01 16.2 0.538 1611
ti = 2098 hrs. 35.21 --- 90
1.31 x 10_§ g Sb(III) 8.02 0.790 100
1.31 x 10 y Sb(V) 13.19 0.6h7 200
,n = 10.5+ 15.67 0.590 300
9.75 y; H = 18. 0.518 389
0.7M g 80% _ 21.1. 0.hh6 98%
2.27 3 HS A- 21.9h 0.h26 555
5.90 g 0191 26.66 0.302 701
0010 M C1 38.20 --" DO
ti = 363 hrs.

96

Original Data from Table II - cont.

 

 

 

 

c/s (l-F) t(hrs.)

1.31 x 10.313 Sb(III) 9.37 0.76% 1+9
1.29 x 10 g Sb(V) 12.98 0.673 101
fi = 1005+ 17063 00556 151
9.75 E H = 22.08 0.khh 200
2.27 g asth 31.51 0.206 390
5.85 g Clgg’ 39.70 --- 00
0.15 A 01

t‘é‘ = 173 hrs.

1.31 x 10.3 ,1; Sb(III) 8.1.7 0.755 15
1.29 x 10 g Sb(V) 11.92 0.670 29
)u = 10.5 17.05 0.507 50
9.75 g 3* , 22.09 0.362 7h
0.7A g 803—" 26.62 0.231 ' 96
2.27 5 HS A 2h.57 0.290 120
5.70 M Cth' 26.71 0.228 1A5
0.30 E 01’ 30.1% 0.129 170
t3 = 66.3 hrs. 3h.60 --- en
1.31 x lo-g g Sb(III) 6.52 0.803 8
1.29 x 10' g Sb(V) 10.01 0.697 19
)u = 10.5+ 1h.63 0.557 1
9.75 a H _ 17.25 0.978 2
0.7M M 503- 18.90 0.&28 51
O.‘00 E C1- 32.98 -"' 60
ti = 39.9 hrs.

 

Original Data from Table II - cont.

97

 

-—L

 

 

 

 

c/s (l-F) t(hrs.)
1.31 x 10"3 y; Sb(III) 16.55 0.818 5
1.30 x 10'3 y. Sb(V) 23.32 0.7% 9
)1 = 10.5 27.98 0.693 15
9.75 y. 11* .. 37. o 0.590 23
0.7M M 50%-- kg. 1 0.519 30
2.27 E 11501, 1+ .15 0.871 35
5.60 y. 01 1; 1.8.61 O.l+66 9
21““ 80°11. 25:53 8'13?» 52

= o 30 e o

6h.gl 0.288 58

91.06 --- oo
1.31 x 10"3 .13 Sb(III) 9.76 0.722 10
1.29 x 10-3 g Sb(V) 17.19 0.510 2
p = 1005+ ' 25.21 0.282 “1+
9751; 11 __ 28.35 0.189 55
0.7 1;: 503' 29.55 0.158 69
2.27 14 HS 1,’ 31.09 0.11% 101
5.50 y; 0101.- 35.10 --— oo
0.50 13 01'
t‘é’ = 31.7 hrs.
1.31 x 103 34 Sb(III) 7.10 0.795 5
1.29 x lo 1; Sb(V) 10.511 0.695 10
p = 10.5+ 19.59 0.578 11+
9.75 11 H = 20.19 0.1118 23
0.7% 3; so.6 21.79 0.370 29
2.27 3; HS 1; 28.91 0.16% 50
5.90 1»; 0101; 30.32 0.123 60
006 y: C].- 3’4’058 "‘ 00
t‘é’ = 2303 hrs.
1.31 x 10'3 M Sb(III) 8.79 0. 1
1.29 x 10"3 E Sb(V) 15.22 0.53». 18
,p.= lO.5+ 17.57 0.862 2%
9.75 g H 19.07 0.916 31
0.7!». 3}; so " 22.50 0.310 1+0
2.27 14 HS 1. 25.07 0.232 50
5.30 g 0101- 32.63 --- 00
0.70 _1_1_ 01"

 

98

 

 

 

 

 

Original Data from Table II - cont.
c/s (l-F) t(hrs.)
1.31 x 10'3 3 Sb(III) 16.60 0.815 3
1.30 x 10-3 3_Sb(V) 23.2 0.792 6
p.= 10.5+ 27.6 0.692 9
9.75 3,8 _ 39.63 0.615 12
2.27 3 H803’ 0.89 0.596 18
5-“0 E 6109' 97.26 0.975 29
0.6 3 01’ 50.02 0.999 27
ti = 25.9 hrs. 55.75 0.380 30
61.52 0.316 33
58.52 0.399 36
60.98 0.322 39
89095 "" °°
1.31 x 10'3 3 Sb(III) 19.19 0.799 3
1.30 x 10-3 3 Sb(V) 27.27 0.708 6
p = 10.5 39.30 0.632 9
9.75 3 H+ _ 2.70 0.592 12
0.79 3 503- 95.95 0.508 15
2.27 3 H803“ 50.19 0.962 18
5.20 3 0103- 56.23 0.397 29
0.80 3 01- 57.89 0.380 27
13 = 21.2 hrs. 65.98 0.298 30
66.27 0.290 33
68.63 0.265 36
93.32 --- oo
1.31 x 10'3.8 Sb(III) 25.00 0.723 9
1.30 x 10"3 3 Sb(V) 39.16 0.566 9
,p = 10.5+ 96.00 0.990 12
9.7g 3 H _ 97.0 0.978 16
0.7 ,3 $03; 61.2 0.320 22
2.27 3 HS ‘ 69.22 0.288 26
5.00 M Cloh- 65.19 0.277 33
1.00 3 01- 68.96 0.291 37
t3 = 20.6 hrs. 71.78 0.209 91
90016 "’ Do

 

 

 

 

 

 

 

Original Data from Table II - cont.
c/s (l-F) t(hrs.)

1.31 x 10'3 3 Sb(III) 21.23 0.766 2
1.30 x 10'3 3 Sb(V) 30.99 0.669 9
)1 =: 10.5 l+0.07 0.559 6
9.73 3 8* _ 95.16 0.50 8
0.7 3 303’ 51.36 0.93 10
2.27 3 Hsoh‘ 51.81 0.929 12
9.50 3 0103' 56.2 0.381 19
1.50 3 01- 62.9 0.306 17
t3 = 12.0 hrs. 90.79 --- oo
1.31 x lo-g 3 Sb(III) 11.88 0.652 9
1.29 x 10' 3 Sb(V) 16.§3 0.531 8
,n = 10.5 21. 0.375 13
9'7E‘E 8* = 39.17 --- 68
0.7 3 803
2.27 3;; H801,"
9.00 3 0103-
2.00 3 01-
tfi = 11.2 hrs.
1.31 x 10'3 3 Sb(III) 23.13 0.795 2
1.30 x 10'3 3 Sb(V) 2.37 0.693 9
)1 = 10.5 1.35 0.59 6
9.75 3,H7 , 97.0 0.982 8
0.79 3 809“ 51.6 0.931 10
2.27 3_HSOu' 58.93 0.356 12
9.00 3 0103' 56.55 0.377 19
2,00 3 01- 67.95 0.257 18
t9 = 10.8 hrs. 75.39 0.169 29

90.76 "’ 00
1.31 x 10"3 3 Sb(III) 22, 1
1.30 x 1073 3 Sb(V) 35,35 8;232 fl
.n.= 10.5+ 93.69 0.508 6
0.7 fl SOI...’ 198.146 0.355 10
..HS 89: 0.... 1w
2-0 .11 01' 88.86 0:23.30 1“
t9 = 10.6 hrs. °°

 

100

Original Data from Table II - cont.

 

 

(l-F) t(hrs.)

c/s

 

2146

10
12
19
co

8250563

7762020

0 O O O O O 0

33.41.5901

2345?99

)

I

I)

IV

(’1‘

bb

SS 0

MPH. S
. r

33 = 14.14 h

.. “Abru-

OO omll mg

11:) 5 COO.

X X 0. M.M_M.M.M_1

101514700:
33:7720012
C O O O O O 0

11 #90292...

 

x.;nXMn£v§M3£1

191514700 =
32 : P/72CC
O O O 0 O1’.‘

11.. #90233...»

 

360.4%
11
8726
7209.
65.42.
0 O o o.
0000
15557
01901
16099
11223
)
I
I)
IV
((
bb
SS
0

Mam. s

.. r
33 = 9L. h
. . 900.
00 08113
115 SHCC3

X X 0 M_M.M_M_M_Q/

191.. 59700:
32.:77200
0 o o o sift

11 u/O/0229t

 

 

01‘ 1g inal Data

frcm Table

II " cont.

101

 

 

—————

 

 

 

 

 

 

c/s (l-F) t(hrs.)
1-31 x 10"3 3 Sb(III) 18.77 0.787 1
1 .30 x 10'3 3 Sb(V) 26.12 0.709 2
‘11 = 10.5+ 9.76 0.606 3
9-75 3 H 1.81 0.526 9
0.79 3 so = 95.79 0.982 5
2 .27 3 H.501; 99.89 0.9 5 6.5
6-00 3 01- 57.80 0.3 5 8
ti- = 6.10 hrs. 6h021 0.272 905
67.27 0.238 11
68.37 0.225 12.5
88026 "" 00
1.31 x 10"3 3 Sb(III) 18. .5g 0.793 1
1.30 x 10-3 3 Sb(V) 25.9 0.715 2
)1 = 10.5 0.628 a
9.75 3 8* .21 0.572
0.79 3 so " 2.05 0.529 5
2.27 3 HS " 97. 78 0.965 6.5
6.00 3 c1- 52. 52 0.912 8
t3 = 7.62 hrs. 57 59 0.356 9.5
63. 00 0.295 11
65.20 0.270 13
89035 -"' 00
ORIGINAL DATA FROM TABLE III
(page 99)
c/s (l-F) t(hrs.)
1.31 x 10"3 3 Sb(III) 6.02 0.693 0.5
1.31 x 10-3 3 Sb(V) 7.11 0.533 1.0
)1 = 10.5+ 55.33 0.952 1.5
9.75 3 H = 63.70 0.369 2.0
0.79 3 so 68.10 0.325 2.5
2.27 3 8801.- 100.99 --- go
9.00 3 0101.-
2.00 3 01-
‘t - = 2.00 hrs.

 

 

102
Lriginal Kata from Table III — cont.

~w-~_ .—

 

 

 

 

c/s (l-F) t(hrs.)
1.31 x 10‘”3 3 Sb(III) 37. 69 0. 619 0.5
1.31 x 10"3 3 Sb(V) 95. 21 0. 593 1.0
p = 10.5+ 59. 60 0. 998 1.5
9.75 3 H 60.19 0. 392 2.0
0.79 3 803= 98. 89 —-- oo
2.27 3 HS ‘
9.00 3 0103'
2.00 3 01-
tfi = 2.22 hrs.
1.31 x 1 '2 3 Sb(III) 26.7 0.736
1.31 x 1 9 3 Sb(V) 29.8 0.705
P = 10. 31022 00691
9.75 3 33.92 0.669
0.79 3 38.23 0. 622
2.27 3 96.56 0539
5.80 3 99.02 0.515
0.20 3 50.96 0. 501
ti = 53. 58.17 0925
60.65 0.900
62.70 0.380
69.79 0.309
100.06 ---
1.31 x 10"3 3 Sb(III) 29.99 0.706 2
1.31 x 10-3 3 Sb(V) 31.57 0.680 5
p = 10.5+ 33.23 0.679 8
9.75 3 H = 37.11 0.636 11
0.79 3 50%5 99.17 0.566 17
2.27 31 HS ' 98. 99 O. 520 22
5.80 3 0103' 99. 00 0. 519 28
0.20 3 01‘ 52.88 0. 981 39
t9 = 58. 2 hrs. 59.99 0 915 99
61.38 0.398 50
62.03 0.383 57
69.28 0.320 66

101.68 _-- 00

1C3

 

 

 

 

 

 

 

CKIGI"AL LATA 3303 31813 :9
(page 53)
c/s (1~F) t(hrs.)

1.31 x 10 333 Sb(III) 9.87 0.783 3
0.695 x 10 3 86(9) 7.22 0.679 5
3p = 12.0 9.16 0.593 8
10.0 3 8* 11.9 0.969 12
6.00 3 01; 13.9 0.380 16
1.99 3 Li 17.67 0.219 29
1088 E C1031. 33055 --- 00
0056 ‘12 SC
2.99 E’HS 3'
t9 = 11.5 hrs.
1.31 x 10"3 3 Sb(III) 5.12 0.896 1
1.29 x 10"3 3 Sb(V) 9.91 0.717 3
‘p = 12.0 12.16 0.6 5 5
10.0 3 8* 15.01 0.5 9 7
6.00 3 01' 19.81 0.905 10
1.99 311+ 20.82 0.379 13
1.88 3 0103- 23.32 0.299 16
0.56 3 503- 33.28 --- 66
2.99 3 HS 3'
ti = 1000 hrs.
1.31 x 10‘3 3 Sb(III) 7.92 0. 783 2
1.29 x 10-3_ Sb(V) 11.20 0 .673 9
,u = 12.0+ 17.25 0. 996 7
10.0 3 H _ 18.00 C. 979 9
6.00 301+ 22.20 0. 351 12
1.99 3 Li _ 23.67 0.308 17
1.88 M 010 39.21 --- 80
0.56 3'503=
2.99 3 HS‘ '
t3 = 10.2 %rs.
1.31 x 10'3 3 Sb(III) 7,08 0 8

1.935 X 10 L Sb(V) 12.92 0:699 %
)1: 12. 0 16.25 0.606 9
1. 99 3 Li“ 91.33 Ciiél 9
1.88 3 0103' °°
0.56 3 sou=
t9 = 6.65 hrs.

 

Original Data

from Table IV — cont.

109

 

 

‘—

 

 

 

 

c/s (l—F) t(hrs.)
1.31 x 10-3 g Sb(III) .55 0.793 1
2.58 x 10-3 g Sb(V) 1 .82 0.678 2
p = 12.0 15.82 0.656 3
10.0 g H+ 22.87 0.503 5
6.00 5_c1‘ 29.92 0.h58 7
1.9% §_Li* 31.51 0.315 9
1.88 g 010 - 95.98 --- oo
0.56 g 50 -
2.HH N H83“-
t3 = 6.h8 hrs.
0.655 x 10’3 5 Sb(III) 5.79 c.7h6 2
1.29 x 10-3 §_Sb(V) 9.35 0.589 5
)1 = 12.0 9065 00576 7
10.0 g H+ 12.09 O.h69 9
6.00 5 01' 1 .77 0.395 12
1.9a 5 11+_ 1 .96 0.365 1%
0.56 y so - 15.06 0.338 17
1.88 g_011h' 22.76 --- Do
20kt; y: H50);-
té = 12.7 hrs.
1.965 x 10'3 g Sb(III) 6.68 0.839 1
1.29 x 10'3 g Sb(V) 19.62 0.6u7 3
1p.= 12.0 19.7% 0.523 5
10.0 g H* 23.50 0.932 7
6.00 g 01; 29.22 0.h15 9
1.uu Q Li 30.56 0.262 12
0.56 5 so ' 2. 8 0.218 1h
1.88 g Cl‘u' 1. 0 --- co
2. M HSC -
ti = 5.9% %rs.
2.62 x 10"3 g Sb(III) 9.09 0.807 1
1.29 x 10-3 g Sb(V) 17.09 0.637 3
)1 = 12.0 23.35 0.50% 5
10-0 E H+ 29.35 0.376 7
6.00 34 Cl" 32. 1+ 0.311 9
1.9% g Li+_ 35.8u 0.238 12
0.56 y sou-_ 38.05 0.191 1M
1088 E;- C10“ L"7006 "" 00
2.49 M 8503'
t% = 6.27 hrs.

f

ORIGINAL DATA FROM TABLE V

 

 

 

 

 

 

(page 5%)
c/s (l-F) t(hrs.)

0.655 x 10"3 y Sb(III) 8.85 0.659 60
1.29 x 10‘3 g Sb(V) 12.95 0.520 89
p = 10.5 13.79 0.968 129
9.75 M 8* _ 16.98 0.368 180
0.79 5 so ’ 18.87 0.272 227
2.27 3 HS 0' 19.91 0.232 290
5.80 y 0104' 22.07 0.199 361
0.20 M C1’ 25.93 --- 00
ti” = E8 hrs.

1.965 x 10-3 §_Sb(III) 10.29 0.799 25
1.29 x 10'3 M Sb(V) 15.36 0.62 50
p.= 10.5 20.02 0.50 75
9.75 g H+ = 23.77 0.916 110
0.79 g 503 30.52 0.250 195
2.27 3 HS 9' 32.39 0.206 180
5.80 5 010““ 9.19 0.160 220
0.20 M 01- 0.72 --- 00
t% = 89.1 hrs.

-3

2.62 x 10 J g Sb(III) 10.57 0.777 20
1.29 x 10'3 m Sb(V) 19.19 0.596 95
p = 10.5+ 25.06 0.972 70
9.75 M H _ 27.88 0.912 96
0.79 g_so ’ 31.90 0.338 120
2.27 5 HS 0' 37.22 0.215 195
5.80 g 0109’ 91.12 0.133 175
0.20 g 01- 97.93 --- 00
t% = 73.7 hrs.

3.93 x 103% §_Sb(III) 10.17 0.805 13
1.29 x 10 M_Sb(V) 18.09 0.659 30
n = 10.5+ 26.96 0.993 50
9.75 E H - 33.90 0.360 75
0.79 g 500' 37.99 0.283 96
2.27 g Hsou' 91.08 0.213 120
5.80 g ClOg' 99.9 0.199 195
0.20 g 01- 95.7 0.129 170
t'é’ = 5609 hrs. 52021 "n' m

I

Criginal Data from Table V - cont.

1C6

 

 

 

 

 

 

c/s (l-F) t(hrs.)

6.55 x 10; lg Sb(III) 11.97 0.801 10
1.29 x 10 g_Sb(V) 19.36 0.665 20
p = 1C.5 3 .68 0.917 95
9.75 g H* _ 3 .36 0.336 56
0.79 u so ’ 93.92 0.298 78
2.27 fi,HS 9' 50.69 0.123 101
5.80 g 010”- 53.23 0.079 120
0.20 g 01' 52.60 0.089 190
ti = 3507 hrs. 57077 --- 00
1.39 x 10"3 g Sb(III) 9.22 0.823 30
0.695 x 10"3 g Sb(V) 8.39 0.699 73
n = 10.5 10.37 0.566 109
9.75 g E+ _ 12.90 0.981 150
0.79 3 so ’ 16.63 0.309 200
2.27 g yséu- 18.75 0.215 299
5.80 g 0100' 20.27 0.151 390
0.20 y 01- 23.90 --— 99
1.31 x 10'3 E Sb(III) 10.79 0.738 26
1.935 x 10‘3 g Sb(V) 16.65 0.595 99
p = 10.; 20.29 0.507 75
9.75 5 H+ _ 26.89 0.397 195
0.79 5 son“ 30.29 0.265 180
2.27 5 8804‘ 35.09 0.198 22
5.80 M 0104- 35.71 0.132 270
0.20 m 01' 91.13 —-- 00
t% = 95.5 hrs.

1.31 x 10'g g Sb(III) 12.23 0.736 22
2.58 x 10' g Sb(V) 19.17 0.586 95
‘p =,10.5+ 29.95 0.972 69
9.75 3 H _ 27.59 0.905 95
0.79 g so 30.17 0.398 120
2.27 g HS 4' 39.98 0.299 195
5.80 g Clch‘ 39.85 0.297 175
0.20 3 01° 38.36 0.171 215
ti = 9"‘03 hI‘S. l'6028 ""'" °0

1C7

 

 

 

 

 

0r iginal Leta frcn: Cable ‘3 — 00m.
c/s (l—F) t(hrs.)
1..;31 x 10‘3 g Sb(III) 5.12 0.882 12
(3.1+19 x 10'3 g Sb(V) 8.90 0.806 2
)1 = 10.5 9.21 0.788 38
9 .75 1_ 13* = 1 .19 0.696 59
0.79 11. soli 1 .61 0.623 72
2 .27 y BSD“- 17.09 0.606 86
c>.20 h 01' 20.61 0.525 102
1:3 = 135 hrs. 22577 0.975 139
25 2 0.909 156
93.36 --- 9°
J..31 x 10’3 g Sb(III) 39.53 0.736 10
13.78 x 10-3 g Sb(V) 93.26 0.670 2
11 = 10.5+ 99.13 0.625 30
9 .75 y H _, 58.91 0.559 93
(3.79 3 so ’ 67.90 0.985 50
2.27 5 H531; 61.92 0.527 60
0.20 311 01- 73.39 0.990 70
5.80 g Clcu’ 80.91 0.386 80
t9 = 78.2 hrs. 87.67 0.3 1 91
86.09 0.3 3 100
89.85 0.352 107
93.87 0.283 120
96.39 0.269 130
99.06 0.299 190
106.00 05191 150
130.97 --- 00
1.31 x 10-3 H Sb(III) 92.91 0.688 10
l+.97 x 10“3 14. Sb(V) 55.37 0.598 20
)1 = 10.5+ 69.66 0.530 31
9.75 E H 71.91 0.977 93
(3.79 h sc.- 75.01 0.955 5
2.27 9 HS: ' 77.77 0.935 60
(3.20 E 01’ 87.96 0.369 70
5.80 M 010 ' 97.68 0.290 80
't9 = 63.1 hrs. 99.50 0.277 91
107.25 0.221 10
96.88 0.296 107
108.05 0.215 120
112.60 0.182 130
109.60 0.203 190
121.91 0.119 150
137060 '"'" 00

108

LIBLIG HAL IATA E’RU-L 'IABIE VI

 

 

 

 

 

(page 58)
c/s (l-F) t(hrs.)
1.31 x 10'3 g Sb(III) 17.12 0.819 16
1.30 x 10"3 g Sb(V) 21.61 0.771 36
5» = 10.1+ 26.05 0.729 57
9.75 E H 31.99 0.667 76
0.20 g 01', 33.61 0.699 97
0.20 9 so,“ 39.76 0.579 111
0.60 g -s 9' 91.80 0.557 131
0.15 y L1+ 95.22 0.521 171
t3 = 220 hrs. 97.79 0.999 196
99.95 —-- °°
1.31 x 10:; g Sb(III) 16.3 0.825 12
1.30 x 10 3 g Sb(V) 19.6 0.789 25
)1 = 10 1+ 21.67 0.767 39
9.75 E H 27.91 0.705 52
0.20 g 01', 30.15 0.676 69
0.25 9 so ’ 39.32 0.631 76
8.90 g c1-u 39.56 0.629 87
0.10 g 11* 39.97 0.576 109
0.75 g HSCu' 92.18 0.597 123
t3 = 221 hrs. 99.06 0.527 19
L5.38 0.512 171
50.11 (.962 19
930C36 "" 00
1.31 x 10'3 g Sb(III) 17.11 0.815 12
1.30 x 10""3 fl Sb(V) 19.28 0.792 29
.n = 10.1+ 22.79 0.759 39
9.75 E E 27.53 0.703 52
0.20 5 01-_ 30.18 0.679 69
0.31 g soh‘_ 33.90 0.639 76
0.99 y 850% 35.31 0.619 87
8-0g 9 ClCh' 39.39 0.579 109
0.0 9 Li+ 92.72 0.539 122
té = 181 hrs. 96.08 0.502 199
52.2 0.935 171
59.2 0.919 197
92057 ""’ 00

 

Original Data

from Table VI - cont.

109

 

 

 

 

 

 

c/s (1-F) t(hrS-)
1.31 x 10"3 h Sb(III) 5.99 0.819 20
1.29 x 10'3 E Sb(V) 10.29 0.715 50
p.= 10.5+ 16.01 0.559 100
9.75 E H 18.85 0.975 192
5.09 E 0109' 21.82 0.399 190
0.20 5 01'_ 29.26 0.325 290
0.37 g soh’ 27.36 0.238 295
1.13 g Hsoh’ 29.29 0.186 339
t% = 152 hrs. 35-92 --~ °°
1.31 x 10’; 5 Sb(III) 16.03 0.808 20
1.30 x 10'“ E Sb(v) 22.19 0.739 95
p = 10.5 29.29 0.699 75
9.75 g h* 39.80 0.582 95
1.13 3 ESGH' 38.95 0.539 115
0-37 E S 5’ 98.55 0.918 195
0.20 g 01 55.13 0.339 215
8.06 g Clgh' 58.76 0.295 290
0.38 9 Li 62.59 0.299 265
t3 = 150 hrs. 83.35 --— 99
1.31 x 10‘3 g Sb(III) 18.27 0.811 12
1.30 x 10"3 g Sb(V) 22.92 0.768 29
)1 = 1C05+ 26026 C0728 36
9.75 g 1 30.05 0.689 98
0.20 g 01'_ 36.87 0.618 61
1.36 3 HSEM' 99.80 0.536 85
7.26 g 0199. 95.21 0.532 96
0.31 M Li 97.38 0.510 108
L3 = 196 hrs. 99.62 0.987 120

51.27 0.969 132

56.35 0.917 150

96.69 --- 90
1.31 x 10“3 g Sb(III) 6.03 0.822 20
1.29 x 10'3 g Sb(V) 13.23 0.610 75
)1 = 1005+ 17075 C.h76 120
9.75 g H 20.80 0.386 165
7.16 h 0103- 23.82 0.297 216
0.20 g 01-_ 27.89 0.177 315
0.52 g sch“ 29.73 0.123 339
1.58 g PSCL‘ 3L.68 --- so
ti = 123 hrs.

!

 

110
Criginal Lata from table VI - cent.

 

 

 

 

 

 

 

C/S (l-F) t(hrs.)
1.31 x 1cj§ 3 58(11:) 18.23 0.*79 SC
1.30 x 10 ~ 8 08(2) 27.90 0. 61 95
‘ : 1C.S .23 L1 0059”: 75
15.75 1, 1* 110.25 0.512 95
1.58 E 8608’ 92.13 0.989 115
0.52 E 805: 99 <3 0.399 190
0.20 3 01 59.95 0.333 195
7.16 y c10h' 56.80 0.311 215
0.23 E 11* 3. 99 0.230 290
Ci : 135 hrs. 69.f7 C.216 265
C2.hC --- °°
1.31 1 10 3 L Sb(III) 19.31 0.831 2
1.30 x 10‘9 3 Sb( ) 19.99 0.769 27
‘p = 10.5+ 23. 88 0.718 39
9.75 k H _ 31. 99 0.623 59
0.57 y sch 39.98 0.587 73
1.73 1 H50; L2.81 0.999 67
0.20 g 01- L3. 50 0.986 102
6.06 i 0109 99./7 C.912 123
0.18 E 11* L9.19 0.920 135
L? = 107 hrs. 59.69 0.295 155
6C.65 C.2CH 1/7
62.99 0.262 199
0L.67 --- 00
1.31 x 10:; L 81111) 22.28 0.728 20
1.30 x 10 7 1 01(9) 32.93 0.605 95
p = 10.54+ 92.93 0.983 75
5.75 8 H 97.27 0.929 95
1.88 3 H002’ 52.99 0.360 115
0.62 8 50k 55.55 0.323 190
0.20 g 01 60.93 0.263 170
6.56 3 0109’ 63.88 0.221 195
0.13 H 11* 66.29 0.192 215
t3 = 97.9 hrs. 71.99 0.129 290
72.90 0.117 265

 

111
Original Late from Table VI - ccnt.

.--
—_

 

 

 

 

 

c/s (l-F) t(hrs.)
1.31 x 10’g‘g Sb(III) 16.71 0.833 8
1.30 x 10'9 3 Sb(V) 98 0.791 15
)1 = 10.5 23. 55 0.765 23
9.75 M 8* 28.19 0.719 31
0.20 E 01'_ 29. 72 0.703 39
0.68 3 so - 36.11 0.690 99
2.07 g 1834' 38.06 0.620 60
6.19 M 0101' 91. 39 0.587 71
0.07 y 11* 96. 99 0.531 80
85 = 118 hrs. 98.53 0.516 86
51.09 0.990 97
53.58 0.965 110
100.18 --- 99
1.31 x 10‘3 g Sb(III) 19.06 0.770 20
1.30 x 10'3 g Sb(V) 27.97 0.662 L«5‘
58.: 10.7+ 36. 63 0.557 75
9.75 11 9 90. 25 0.513 95
2.57 g 8001' L7. 66 0.929 115
0.20 M 01- 50.15 0.399 190
0.83 g 801: 50.99 0.389 152
5.99 g 0103‘ 55. 22 0.332 170
0.12 g 11* 59.38 0.282 195
ti = 111 hrs. 05. 56 C.207 215
66.20 0.200 290
08.67 0.170 265
82.71 --- 06
1.31 x 10"3 g Sb(III) 18. 65 0.771 20
1.30 x 10’3 3 Sb(V) 28 .91 0.652 95
5n = lO.7+ 92.C2 C.L05 5
9-75 E H ’3 27 0.970 ,5
2.87 g 1003' 96. 60 0.929 115
0.20 3 01'; 59.78 0.328 170
0.93 8 SC ’ 60. 26 0.261 195
9.82 L 01 3’ 61. 35 0.298 215
83 = 129 hrs. 03.79 0.219 290
81.57 ——- 00

0' "9M ah.— ~-3,m---~.‘_ 9h”-

 

112'
Criginal Data from Table VI - cont.

 

 

 

 

 

1.31 x 10'5 y Sb(III) 18.0 0.788 20
1.30 x 10'3 g Sb(V) 27.27 0.679 #5
,u = 11.0+ 37.30 c.561 75
9.75 M H h3.5” C.h88 95
3,uu E HSCL' L5.09 0.h70 115
0.20 5 01‘, ht.h2 0.b31 190
1.06 g s ' 51.12 0.399 152
9.19 g 01 0' 53.67 0.369 170
0.20 5 11* 59.02 0.306 195
t3 = 136 hrs. 63.06 0.259 215

€b.25 0.2h5 2&0

65.32 0.232 265

85.08 --- °°
1.31 x lo-g y Sb(III) 17.52 0.800 20
1.30 x 10' m Sb(V) 26.25 0.700 15
11 = 11.0+ 35.33 0.595“ 75
9.75 g H MC.62 0.535 95
3.66 g 3001’ LL.13 0.995 115
0.20 g 01'- 52.27 0.u02 152
1.1% g s ’ 53.65 0.386 170
3.72 g 010u‘ 60.h8 0.308 195
0.11 Q Li* 61.92 0.292 215
ti = 127 hrs. 67.03 0.233 2h0

69.20 0.209 265

E7.hh —-— oo
1.31 x 10"3 L Sb(III) 16.3h 0.613 20
1.30 x 10'3 g Sb(V) 25.06 0.719 L5
,n = 11.0+ 32.50 0.629 75
9.75 g H 3 .50 0.572 95
3.88 3 LSC L0.55 0.537 115
0.20 g 01'- 59.02 0.997 1LC
1.20 g 000’ M6 5h 0.L66 152
3.32 5 0101' b9.he C.h35 170
0.05 E Li 55.8% 0.362 195
t3 : 156 hrs. 58.03 0.337 215

01.35 0.299 290

97.52 --- oo

Criginal Kata

._.. “..~.-.._-

frcm Table

VI - cont.

113

 

‘

w“.— -

 

 

 

 

 

 

 

c/s (1-P) t(hrs.)
1.31 x 10'8 g 011 11) 16.98 0.309 2
1.30 x 10"3 g Sb(V) 23.50 0.732 95
I» = 11.04 30.76 0.6Lg 75
9.75 g H 35.20 0.558 95
b.05 g 250““ 38.55 0.560 115
0.20 1 01', h1.96 0.521 190
1.25 g 80 ’_ 59.03 0.597 152
3.00 g 010% 58.22 0.950 170
ti = 181 hrs. 52.Cl C.L06 195

59.85 0.317 265

07.60 ---

LnIGIYAL DATA FRCN TABLE v11

( page 60 )

c/s (l-F) t(hrs.)
1.31 x 10‘3 g Sb(III) 18.66 0.787 1
1.30 x 10'3 g Sb(V) 2h.65 0.718 2
,n = 10.1+ 30.19 0.65 3
9.75 y H 37.62 0.570 n
6.00 g 01'_ 50.75 0.535 5
0.2 5 801’ 99.98 0.h29 6.5
0.60 g ESOh' 52.35 0.902 8
2.70 g C1QH' 57.83 0.3h0 9.5
0.15 3 Li 62.39 0.287 11

3 = 7.02 1rs. 65.10 0.257 12.5

87.56 ~-- 60
1.31 x 1c:§ g Sb(III) 18.57 0.791 1
1.30 x 10 E Sb(V) 25.29 0.716 2
A1 =- 1C05+ 32075 0.632 3
9.75 E H _ 2.15 0.526 M
6.00 y 01 , 55.96 C.h8 5
0.52 m s ’ h9.56 0.593 6.5
1.58 M as. ’ 55.30 0.379 8
1.36 g 0100- 56.01 0.371 9.5
0.23 g 11* 62. 5 0.299 11
t3 = 7.65 hrs. 69. 8 0.271 12.5

59.0C --~ 00

Criginal Data from Table VII - ccnt.

L

11J+

“

 

 

 

 

 

 

 

c/s (l-F) t(hrs.)
1.31 x 10:§ 3 Sb( 11) 18.53 0.793 1
1.30 x 10 g Sb(V) 25.98 0.715 2
,u = 10.5+ 33.25 0.628 3
9.75 E H _ 38.21 0.572 n
6.00 g 01 _ 52.05 0.529 5
0.7M 5 003’ 97.78 0.965 6.5
2.27 5 2803- 52.52 0.912 8
t9 = 7.62 hrs 57.51+ 0.356 9.5
63.00 0.295 11
65.20 0.270 13
t9035 "' 0Q
ChIGINAL DATA FROM TABLE VIII
( page 60 )
c/s (l-F) t(hrs.)
1.31 x 10-3 g Sb(III) 11.38 0.880 7
1.30 x 10"3 g Sb(V) 19.29 0.8L9 1h
)2 = 9-CO+ 19.52 0.897 21
8.00 g H 16.98 0.821 28
0.79 5 so, 17.02 0.820 35
1.86 1 ES 9' 18.69 0.803 98
0.2- g 01’ 21.18 0.776 51
0.2 L L1+ _ 23.88 0.798 58
h. 2 g 0159 26.2 0.723 71
ti = 255 hrs. 26.93 0.716 82
28.33 0.701 93
9Lo71 "" 00
1.31 x 10 3 5 Sb(III) 18.78 0.850 7
1-3C x 1C'3 E Sb(V) 15. 5 0.838 19
9.: 9.00+ 17.31 0.829 21
c.25 g H 19.02 0.806 28
0.20 5 01‘: 19.91 0.797 5
0.7% M so _ 29.11 0.755 86
1.92 if! 1151+ 26.196 0.730 53
9.65 g 0100’ 27.99 0.720 :9
ti = 201 hrs. 31.62 0.678 71
33.1% C.662 92
58.13 --- so

 

 

Criginal Leta from Table VIII - cont.

‘0’-" ‘ ., ‘, ..~ ~'-.

 

 

 

 

 

 

 

c/s (l-F) t(rrs.)
1.31 y 10’; L Sb(II 16.38 0.835 8
1'3C6quo- L Sb(V) 1§.g§ $.31E 1%
- : l'-- A 2 .‘J J ‘0 C‘ 2’)
’8.50 g 8* 23.55 0.762 2;
0.20 N 0 _ 26.26 0.735 38
C.7h K E ' 28.75 C-7C9 L6
1.9% E hsgh’ 39.68 0.6L9 5M
5.19 M 010 ’ 36.82 0.628 62
0.26 E 11* 38.75 0.608 71
t5 = 135 hrs. 52.65 0.569 81
55.75 0.557 eh
58.59 C.SlC 1C6
98.87 --- oo
1.31 x 10'3 h Sb(III) 13.95 0.832 10
1.30 x 10'3 g Sb(V) 20.23 0.759 25
8.75 y H+ = 32.21 0.612 50
0.75 g 806 36.91 0.556 60
2.00 g 000%“ 30.05 0.518 75
0.20 h 01’ .20 0.h 2 9'
5.68 F 010;“ 57.5 0.325 11%
0.61 E 11+ 57.97 0.308 125
t3 = 91.7 hrs. 58.29 0.298 195
59.69 0.282 155
€3.09 "" 0°
1'31 x 10-3 5 Sb 13.23 0.8EIW” 10
.30 x 10‘ 5 Sb 21.19 {,7L5 25
.n = 10.1 23.88 0.713 35
9-00 z,H+ _ 30.29 0.636 50
0.79 g 20 “ 33.21 0.601 60
0.20 g 01' 56.76 0.538 c8
5.62 g 010L* 53.28 0.359 110
0.36 y 11*' 57.6% 0.307 12:
ti = 57.7 “5.05 0.338 1M5
61.01 0.267 155
83.18 --- 88

 

Criginal Eat; frcm Table VIII — cont.

 

 

 

 

 

 

 

 

 

c/s (l-V) t(hrs.

1.31 x 10"3 g Sb(III) .91 0.817 8
1.30 x 10‘3 g Sb(V) 22.02 0.781 15
‘0 = 10.1.+ 26.36 0.738 23
9.00 h E 30.37 0.698 31
0.20 F 01', 31.89 0.683 39
0.79 E sch” 91.21 0.590 69
2.06 h Hsch' 9.53 0.557 60
5.62 T 0105- 50. 69 0.996 71
0.36 E 11* 55.05 0.963 80
15 = 91.3 hrs. 55.20 0.851 86
58.97 0.913 97

60.22 0.501 109

lCO.§H --- 00

1.31 x 1-Ԥ g 28(1111 1L.62 0.829 12
1.3C X 1C- L Sb(V) 21.f‘(:, 0.7}40 2'7
11 = 10.1+ EL.SC* C.7C5 39
5.25 g H - 31.45 0.622 5H
0.79 3 SO&' 37.92 0.527 72
2~11 8 2898' 52.02 0.L95 87
0.20 g 01 _ 98.99 0.L17 102
5.66 5 010 L6.h7 0.951 120
0.11 y 11* 53.68 0.358 135
:3 = 11% hrs. 59. 5 0.393 56
58.8; 0.2 2 177

61.01 0.266 199

83.13 --- 00

1.31 X 10:; h Sb(III) 16.99 0.816 0
1.30 x 10 5 5: 86(1) 21. 7 0.761 26
,M = 10.53 29.16 0.666 H0
9'25 E F 37-96 0.575 61
(.75 5.5 08,52 C.SC2 79
2.15 g 280L- 50.62 C.hLE 59
C.2O 5 01' 51.11 C.L28 109
‘.93 E C100” Eh. 3C 0.393 13c
(.51 E Li+ 59 39 0.336 150
t; = 118 hrs. 62.00 0.307 170
65.66 0.266 195

71.62 0.199 250

EQ.L1 --- 00

 

117

Crigi 31 Date from Table VIII — cont.

(1—7)

 

 

.)

t(hrs

c/s

 

 

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Table VIII — cont.

 

 

 

 

 

 

 

 

c/s (l-F) t(hrq )
1.31 x 10'? g Sb(III) 1h.h€ c.8h6 15
1.3c x 10‘3 g Sb(V) 16.h1 0.825 36
.n = 11.7 + 20.h2 c.783 56
11.cc L F 2h.1h c.7L3 76
c.7h 5 so - 26.88 c.71fi 96
1.13 ; HS u- 27.8c C.7Ch 111
c.2o g 01’ 3C.6P c.673 132
6.19 g 010%“ 2.8M 0.650 150
t3 = 367 hrs. 3h.69 0.631 171

36.71 c.6c9 196

93.91 —-- en

CAISIUAL IATA FRCM 11112 IX

( rage 63 )

c/s (l-F) t(hrs.)
1.31 x 1c-% 3 Sb(III) 2%. MM c.725 1.5
1.3C x 1C” L Sb(V) 33.15 c.627 3
l) = 1C.5+ 39.+}+ (3.556 Li,‘f
6.00 g H _ L5.96 C.LE3 6
c.7u g so ' 52.8c c.h06 7.5
1.86 g 35%u' TC.3O 0.367 9
6.CC 3 Cl“ 58.23 0.3%5 1c.5
C.h2 g Clcu' €8.92 --- oo
1.76 k Li+
1.31 x 10‘3 g Sb(III) 21.82 0.750 1.5
1.3c x 10’3 L Sb(V) 31.05 0,6u5 3
)u = 10.§+ 39.31 0.550 &.5
8,5c E H _ LL.5§ C.h90 5
0.7% 5 so.’ h8.9. c.h39 7.5
1.86 E F53h- 53.9% C.383 9
3.90 5 c1“ 59.2 c.322 10.5

.30 1 CIC ‘ 97.37 ---

1.26 L 11*” 0°
ti = 7.66 hrs.

119

 

 

 

 

 

 

 

 

 

 

 

 

Crigina] Leta frcm Table IX - cont.

c/s (l-F) {Thrstj
1.31 x 10“; L Sb(III) 18.53 0.793 1
1.30 x 10-2 E Sb(V) 25.h8 0.715 2
M = 1C.E 3 .25 0.628 3
2.75 g 2* 3..21 0.572 A
6.00 g 01‘, h2.05 0.529 5
0.7M 3 SC ’ L7.78 0.h65 605
2.27 g 2500* 52.52 0.h12 a
t% = 7.62 hrs. 7.5“ C-356 9.5

63.00 0.295 11

65.20 0.270 13

{-9.35 --..
1.31 x 10:; L Sb(III 22.18 0.758 1.5
1.30 x 10 E Sb(V) 30.51 0.667 3
M = 11 C 36.6% Coé‘CC 24.5
10.25 3 H*_ h3.12 0.529 6
0.7M g 50 ’ h7.78 0.u78 7.5
2.09 5 HSEh' 52.9, 0.322 9
6.00 5 01- 57.15 0.376 10.5
0.26 M 010”“ 91.54 --- 00
t'f: = .96 hrs.
1.31 x 103% L Sb(III) 20.53 0.773 1.5
1.30 x 10 y Sb(V) 28.30 C.6E8 3
,u = 11.7 33.17 0.623 5.5
11.00 g 2* 39.89 0.560 6
0.7% M sc_= Q6.89 0.583 7.5
3.13 g 2803‘ 50.62 C.hhl 9
6.00 g 01' 53.1h 0.h1h 10.5
0.39 E 0103' 56.02 0.362 2
t3 = 10.1 hrs. €0.63 -—- 'QO

03,01"11 DATA FRCM 11215 X

( page 80 )

c/s (l-F) t(hrs.)
1.31 x 10-3 g Sb(III) 3.8% 0,586 10
1.29 x %o-3 1 Sb(V) 5.73 ..827 25
9.75 g H+ _ 10.98 SIZE? ;i
0.7% E 800’ 1h.67 0.563 97
2.27 g 2503' 15.09 0,651 167
5.50 E Cng‘ 22.51 c.129 196
C.20 E C1- 27.C C.i9h 290
t% = 123 hrs. 33.5 ___ 60

 

Original Lata from Table X - cont.

A .-

.-~ - H— ‘ c...- <¢—".-_

 

 

 

 

—---s--~vV _. —.-

 

 

 

 

 

 

c/s (l—F t(hrs.)
1.31 r 10-; ; 0b(I:I) 7.77 0.778 29
1.29 x lC'r 1 "b( ) 13.h1 0.617 60
.0 : 10.57 “ 18.36 0.975 100
9.75 1 2* - 21.35 0.389 195
0.7% L sch“ 27.21 0.222 220
2.27 E 200;“ :8.L7 0.186 268
5.80 g 010 - 3L.€7 --- oo
0.20 g 01-
té = 115 hrs.
1.31 x 10*3 g 00(111) 6.71 0.811 20
1.29 x 10‘3 ; Sb(V) 12.51 0.6h7 50
2.: 10.54 19.60 0.hh7 100
9.75 g H 22.13 0.375 190
5.80 g 010L‘ 2h.86 0.298 190
0.20 g 01" 27.58 0.222 240
0.72 g 80 ’ 30.98 0.110. 296
2.27 K HS - 35. 3 m" 00
1.31 x 10-3 5 Sb(III) 16.69 0.826 13
1.30 x 10-3 g Sb(V) 23.00 0.760 25
.n = 10.5+ 27.78 0.710 90
9.75 E H _ 33.76 0.698 55
0.79 3 so 9.08 0.593 73
0.20 3 01‘ L8.31 0.996 100
5.80 g 0100 51.02 0.968 120
t9 = 121 hrs. 56.91 0.907 135
59.59 0.379 155
65.29 0.320 173
72.0% 0.2h9 220
95.91 --- 90
1.31 X 10' M Sb(IIf} 1 .0r 0
1.30 x 10'gg Sb(V) 25.9§ gzgg% E?
.u = 10-7+ 37.22 c.55u 6:
c. r: 1/
/°// 2! H 99.63 0.1-+65 OK,
9-7“ 2 SC _ 97.97 0.225 113
4-30 8 HS 2 51.00 0.388 120
0.20 fl 01’ 53.08 0 6:
. 7 - .3 s 152
5.97 h 0100 55.90 0 336 170
. V + ,. °
0.20 L‘ Li 60.5d C.27L} 1Cl’4
ti = 115 hrs. 63.LL 0.239 2i?
33.32 0.167 205

 

(riginal Eata frcm Table X - cont.

 

A
H

r11
V

 

rm oxv‘ho

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c/s

1.31 x 10'; g Sb(III) 10.71
1.30 x 10’ 1 Sb(V) 29.71
».= 11.01 35.56
9.7: 2 H 39.53
2.39 E L301- L5.§6
0.20 g 01- 99.80
0.79 3 s0 - 57.59
6.18 z C1 M. 61.99
0.50 3|11+ 68.53
t% = 112 Yrs 82.21
1.31 x 10"3 g Sb(III) n.98
1.29 x 10"3 x Sb(V) 7.22
An = 10.5 9.98
9.75 g H* _ 12.99
0.72 3 SC ’ 19.17
2.27 5 2080‘ 17.16
5.80 a 0100’ 20.31
0.20 g 01- 35.7
t% = 111 hrs.
1.31 x 10'3 g Sb(III) 5.31
1.29 x 10'3 g Sb(V) 7.02
.p = 10.5 9.27
9.75 5 H* _ 12.20
0.79 g 503' 13. 5
2.27 g 300““ 17.1L
5.80 m 0101- 18.99
0.20 g 01- 5.62
ti = 122 hrs.
1.31 x 10'3 y bt(:1I) 15.h9
1.30 x 10’3 3 Sb(‘) 17.28
‘p = 10.5+ 22.91
0.79 g 8‘,“ 33.90
2.27 g ES~ ' 36.L5
5.80 g 010%“ 39.19
t3 = 121 hrs. 97.01

58.02

09.73

3

1\. _
k "’m

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1.11.:

 

 

Cripinal fate fzcm Table K — Ccnt.

 

 

 

 

c/s (l-F) t(hrs.)

1.31 x 10:; g Sb(III) 15.2 0.835 10
1.30 x 10 g Sb(V) 18.88 0.795 21
u = 10.5 21.27 0.769 30
9.75 2 5* 25.52 0.735 39
0.7h g sck' 27.97 0.697 50
2.27 L HS M' 33.96 0.637 60
5.80 g 0100’ 35.69 0.613 69
0.20 3 01- 36.70 0.602 80
ti = 123 hrs. 93.37 0.530 95
95.31 0.509 107

52.21 0.939 122

92.2% "'""" 00

1.31 x 10‘3 g Sb(III) 15.89 0.893 10
1.30 x 10“3 g Sb(V) 22.39 0.779 20
.u = 10.5 27.21 0.731 29
9.75 M 2* 28.58 0.717 37
0.20 3 01-_ 33.92 0.669 07
0.79 g 50 ' 39.11 0.613 60
2.27 1v; IS h- z+3.71 0.567 72
5.80 g Clch' 95.80 0.596 83
t9 = 122 lrs. 98.29 0.522 .5
59.19 0.969 108

61.31 0.391 1h2

100.99 --- so