THE PREPARAHON M9 PROPERTIES OF EORON YRISELEMDE Thai: 901 1+» Dogma oi M. S. MICHIGM‘ STATE UNIVERSITY WifiEéam Earl Hufchinson 1960 LIBRARY 0 ‘L’ Mlcl'gan 83303 S m, University '.. ‘ *fl “A «'2’ “salt " :GAN ' n . l I I C EAST LANSH‘V‘“, Ml ABSTRACT THE PREPARATION AND PROPERTIES OF BORON TRISELENIDE by William Earl Hutchinson Boron triselenide was formed by passing selenium vapor over amorphous boron at 850° to 950°. A hydrogen sweep was employed and BZSe3, a yellow powder, was collected on a fritted disk. The boron triselenide was amorphous as formed, but after being heated to a temperature between 195° and 235°, it be- came crystalline. Both forms were studied by infrared tech- niques and the characteristic bands were noted. X-ray powder photographs were taken of the crystalline form and "d-values" were calculated. These values were compared with those of the hexagonal and cubic forms of boric oxide and were similar to the values of the cubic form. Melting point determinations were run and the solid product was found to decompose at 556i5° in an evacuated ampoule. The solubility of boron triselenide in various liquids was investigated, but because of its extreme moisture sensitivity, the accuracy of these findings is doubtful. The reaction between boron and tellurium was attempted, but no reaction occurred. THE PREPARATION AND PROPERTIES OF BORON TRISELENIDE BY William Earl Hutchinson A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Chemistry 1960 ACKNOWLEDGMENTS I wish to express my sincere thanks to Dr. Harry A. Eick for his patience, help and encouragement during the course of this work. To the Dow Corning Corporation for their liberal policy on educational leave and financial assistance, I am also grateful. My thanks and gratitude are also given to other members of the chemistry department for their assistance. Lastly, I am indebted to my wife for her understanding and encouragement throughout the course of my work, both in Midland and on campus. 11 TABLE OF CONTENTS Chapter INTRODUCTION Historical Purpose of Study EXPERIMENTAL Raw'Materials Reactions Between Boron and Sulfur Reactions Between Boron and Selenium Analytical Procedures Qualitative tests Quantitative tests Measurement of Physical Properties Melting point determinations Determination of X-ray powder data Determination of infrared spectral data Determination of Solubility Data Reactions Between Boron and Tellurium RESUETS Sulfur-Boron Reactions Selenium-Boron Reactions Characterization of Product Melting Point (Decomposition Point) X-ray Powder Data Infrared Spectral Data Solubilities Boron-Tellurium Reaction SUMMARY Suggestions for Future Research BIBLIOGRAPHY APPENDICES iii LIST OF TABLES Table I Quantitative Results of Percent Selenium in Product II X-ray Spectral Data, "d values" III Infrared Bands - Amorphous and Crystalline Products iv Page 38 #2 #5 LIST OF Figure I Reaction apparatus II Reaction apparatus III Reaction apparatus IV Reaction apparatus V Reaction apparatus VI Reaction apparatus for Series for Series for Series for Series for Series for Series FIGURES II III IV V X XII VII Infrared spectra for amorphous product from 2 to 15 microns VIII Infrared spectra for amorphous product from 15 to 37 microns IX Infrared spectra for crystalline product from 2 to 15 microns X Infrared spectra for amorphous product after exposure to air Page 10 ll 12 18 21 M7 #8 ’+9 LIST OF APPENDICES Appendix A. Details of Series III, IV, and V apparatus changes B Calculation of percent selenium C Calculation of percent boron D Reading of X~ray film and calculation of "d values" vi Page 56 59 60 61 INTRODUCTION fiistoricgl The reaction between boron and the chalcogenides was investigated by many persons prior to 1900. Berzeliusl reported in 182% that boron trisulfide could be formed by melting sulfur in the presence of boron. In 1858, WOhler and St. C. Deville2 reported the preparation of the sulfide by the reaction of hydrogen sulfide with heated boron. In the early 1890's, Sabatier3 and Moissany, following the work of Wehler and St. C. Devillez, also prepared boron trisulfide and attempted to prepare its analog, boron triselenide. Sabatiers found that the selenide could be prepared by passing hydrogen selenide over boron maintained at a bright red heat. Moissan6’7 reported that selenium and boron would react at 610° to form boron triselenide. No additional work pertaining to the preparation and proper- ties of this substance has been reported. Even at that time the majority of the investigations were carried out with boron and sulfur and their reaction product, boron trisulfide. Both Moissan and Sabatier reported that the selenide reacted violently with water with the evolution of hydrogen selenide. This action was comparable to the reaction of boron trisulfide with water; a reaction which was accompan- ied by the evolution of hydrogen sulfide. These investiga- tors,therefore,assumed that other reactions of boron tri- selenide would be the same as those of the corresponding 2 sulfide, but they reported no further experiments to prove this hypothesis. In 1926, Tiede and Thimann8 again examined a modification of the sulfide reaction. They reported the formation of boron trisulfide by the reaction of boric oxide with aluminum sulfide at 12000 to 13000. The product formed in this re- action was contaminated with silicon sulfide which was formed through the reaction of the aluminum sulfide with the quartz reaction tube. The reaction of boric oxide with aluminum selenide was not reported. In the last few years the renewed interest in boron chemistry has led a few persons to re-examine boron trisulfide, but no one has reported data on boron triselenide. Zeeman9, in 1950, published an article on the spectrum and structure of the boron monosulfide (BS) molecule. His apparatus con- sisted of a Pyrex glass vacuum system and a quartz discharge tube of the end-on type. Helium or argon was pumped through the system at low pressure with a mercury diffusion pump. Amorphous boron was placed in a silica boat which was containai in a quartz tube, while a reservoir which was filled with vacuum distilled sulfur protruded downward from the discharge tube and, when heated, provided sulfur vapor. This vapor was carried by the circulating gas over the boron which was heated by means of a cylindrical electrical heater. At about 700° the brilliant S2-spectrum which was present at the early stages of the process disappeared and was superseded by a very intense spectrum resembling a "daylight" fluorescent lamp. 3 In a more recent study Greene and Margrave10 reported additional spectral data on the boron monosulfide molecule. Their work was also conducted in the vapor phase. For their work, dried hydrogen sulfide was passed over amorphous boron at 700° and the vaporized product was collected on a cold finger. This product was introduced directly into a 2.5” centimeter diameter quartz or Vycor tube to which suitable windows had been attached. The Spectrum of the gas over the boron trisulfide was examined by emission and absorption techniques; five bands were observed. The isotopic shifts which resulted from the enrichment of the boron sulfide with B10 gave support to a twisted zigzag model possessing 02 symmetry. These recent investigations did not include the examin- ation of the boron-selenium reaction. Weféméx The purpose of the present study was to determine a suitable method for the preparation of boron triselenide, to investigate some of its physical preperties, and to study some of its reactions. The lack of past knowledge of this compound and the availability of high purity raw materials led to the belief that this was a worthwhile endeavor. EXPERIMENTAL R__..aw Materials. The following raw materials were used throughout the present study. The purity and suppliers of these materials are listed when known. 1. Crystalline boron - 100 mesh U. S. Borax and Chemical Corporation 50 Rockefeller Plaza New York 20, New York Electrolytic boron - 99% purity Fairmount Chemical Company, Inc. 117 Blanchard Street Newark, New Jersey Sulfur - Triply distilled Purity and source unknown Selenium metal - 99.99% pure powder Fairmount Chemical Company, Inc. 117 Blanchard Street Newark, New Jersey Prepurified nitrogen The Matheson Company, Inc. East Rutherford, New Jersey Hydrogen gas Ohio Chemical and Surgical Equipment Company Cleveland, Ohio Argon gas The Matheson Company, Inc. East Rutherford, New Jersey Tantalum foil Fansteel Metallurgical Company North Chicago, Illinois Molybdenum foil Fansteel Metallurgical Company North Chicago, Illinois 5 Reactions Between Boron and Sulfur The preliminary work in the present study was carried out to determine the general type of equipment that would be needed to obtain good yields of product. In order to arrive at the best equipment design, the reaction between boron and sulfur was examined using the conditions reported by previous investigators. Eight series of reactions were run; each resulting in a modification of the equipment design. -§2£is§ I To prove that a product could be formed when boron was reacted with sulfur, a simple, but crude, apparatus was set up“. This apparatus consisted ofa 2.5 centimeter diameter Vycor tube, 66 centimeters in length, which was inserted into a tube resistanCe furnace. Crystalline'boron was placed in a Vycor boat which was then set in the tube. A quantity of sulfur was also added to the tube at the inlet end, outside of the heated zone. Rubber stoppers containing Pyrex tubing were placed in each end of the Vycor reaction tube. Pre- purified nitrogen was passed through the inlet end of the system at an approximate rate of ten cubic centimeters per minute. The outlet end of the system was equipped with Tygon tubing which dipped into a water trap. A stream of air was directed at the outlet end of the reaction tube to cool it so that product crystallization could occur. A Chromel p-Alumel thermocouple, attached to a Minne- apolis Honeywell Model 2730 potentiometer, was placed inside 6 the furnace to measure the temperature. A measurement of temperature, accurate to 35°, could be made by first stand- ardizing the potentiometer at room temperature and then measuring the millivolt potential difference when the thermo- couple was heated. By comparing this millivolt reading with a standard chart the true temperature could be determined. This experiment was repeated varying the furnace temperature from 6000 to 7hO°. Although a few small white crystals were formed at 680°, a higher yield was observed at 730°. The small amount of white crystals that was obtained was placed in water and found to be very soluble. Upon exposure to air these crystals emitted hydrogen sulfide. The above properties were identical with some of those previously reported for boron trisulfide. The poor yield of white material led to the belief that the rubber stoppers and Tygon tubing provided areas for product to escape. In an attempt to increase this yield a new apparatus was designed. Series II The failure of the apparatus described in Series I, page 5, led to the new apparatus as shown in Figure I. All of the glass-to-glass Joints, except F, are lh/35fjoints. The 1.7 centimeter diameter Vycor reaction tube, B, was in- dented to promote turbulence and a longer contact time be- tween the sulfur vapor and the crystalline boron, C. The boron was also spread thinly over the bottom of the tube to expose more surface for reaction. Triply-distilled sulfur, E, was placed in the 250 milliter flask, D, and prepurified nitrogen was used to sweep the system. After passing through the heated tube, A, the nitrogen was bubbled into a water trap at the approximate rate of ten cubic centimeters per minute. The furnace was maintained at 730° throughout the two hour reaction. This arrangement also proved ineffective because it was difficult to carry enough sulfur vapor into the heated tube, even when the sulfur was boiled. No product formed in the cooled portion of the tube. The possibility of leakage at Joint F resulted in replacing it with a standard tapered Joint. The series of reactions using this setup was desig- nated as Series III. .H WEDGE. psmasm I m xmmaw Roamm n a coeon ocdaamummno u 0 one» noom> I m oomcusm I < 0 15a... 0P ~Z . _ ”v ,H HMIIII\. .\\\ir 1(MWWWWWWWMWJhTAMJHWhWHJlN inept: N:< , 023000 § < Hnnflutdm Lou. mflvdsllldx logger— ._.1;___.56 188 11.1., .11, sag I An apparatus as shown in Figure II proved to be the basic apparatus which, after being modified as in Figures III and IV, was used for subsequent reactions between boron and sulfur. The transition of the flask, D, from the long necked flask of Figure II to the short necked flask of Figure IV was prompted by the need for getting sulfur vapor into the heated tube in sufficient quantity to promote reaction. A detailed explanation of these three series will be found in Appendix A. HH .wm30_u nmmmopw nonnsm I u asuasm I m Emma“ xonmm I a , cones ocaaampmmno I 0 AH 09:» noom> I m oomcpsh I 4 I I . I IIA“HP IHUIlIlJfi m_< IIII \ . . 023000 . V K \4 <. . . u H ”UV-0m $0.... 0.5.9.6344 £03060”. 4 ”Seer; 0L ~z 11 HF MEDGE psaasm I m Madam Roman I n conon ocaflampmmno I u was» hoom> I m oomcnsm I < Ill"!!! H ”020...." £09. m3¥656QQ< convudflm 12 HH WEDGE. pumazm I m Mama“ Koamm I n meson ocaaampmmno I 0 open noom> I m oomcnsm I < < Hmdmtum so“? ODVOLOGQ< COBU‘OC 13 fifitlflilll After approximately ten reactions at temperatures of 700° to 7Ao°, the indented Vycor reaction tube of Figures I through IV cracked. The boron apparently reacted with the Vycor, particularly at the indentations, deveIOping a form, perhaps similar to Pyrex, which set up strains in the tube because of the difference in expansion. This inability to place the boron in direct contact with the Vycor reaction tube led to a search for a better carrier for the boron. A piece of 0.018 centimeter molybdenum foil, approxi- mately 1.3 centimeters by 7.5 centimeters, was bent to resemble a boat. To this assembly was added a quantity of crystalline boron. The boat was then placed in the 2.5 centimeter diameter Vycor tube of Series I, page 5, and a reaction was run. After a reaction time of two hours at 720°, the apparatus was cooled and the reaction tube was inspected. Little or no product was formed even though sulfur vapor had been carried into the reaction zone as evidenced by a slight precipitate of sulfur at the outlet end of the reaction tube. However, the molybdenum boat was adhered to the Vycor tube with a syrupy red fluid. The sulfur vapor had apparently reacted with the molybdenum foil. When the reaction system cooled, the Vycor tube cracked at the molyb- denum-Vycor interface. Molybdenum foil was, therefore, abandoned as a carrier for the boron. 11+ Series 1;; In the next series of reactions, a tantalum boat was substituted for the molybdenum boat. A piece of 0.013 centi- meter tantalum foil, approximately 1.3 centimeters by 7.5 centimeters, was formed into a shallow boat by bending. To this boat was added crystalline boron. The boron was then placed in a 2.5 centimeter diameter Vycor tube, similar to the one described in Series I, page 5, with a quantity of sulfur at the inlet end. After several hours of reaction, using a nitrogen sweep, no reaction occurred between the sulfur and the tantalum foil, the boron and the tantalum foil, or the nitrogen and the tantalum foil. A small amount of white material formed during the reaction. The tantalum foil, therefore, appeared «adequate. as a carrier for the boron. 15 §2I12§.YIII The previous series of reactions, using the prepurified nitrogen sweep, demonstrated that the crystalline boron was caked badly after the reactions were run. The compacted boron also smelled strongly of sulfur. These observations might be explained by postulating that the sulfur vapor was poisoning the surface of the boron, causing it to cake, and lessening the surface available for reaction. A dry hydrogen sweep was substituted for the nitrogen sweep on the assumption that the hydrogen would react with the surface sulfur to form hydrogen sulfide, or more logically the monohydrogen sulfide (HS) forma. This reaction would keep the surface fresh for further reaction because of the volatility of the hydrogen sulfide gas. After a two hour reaction time at 7h0°, some white crystals formed. a. Mellor11 reports that hydrogen sulfide begins to dis- sociate at MOOO, ultimately to hydrogen and sulfur at 17000. l6 Reactions Between Boron and Selenium Series I; To determine whether selenium and boron would react, a series of reactions were run in an apparatus similar to that used previously in Series 1, page 5. Selenium (99.99% pure) was placed at the inlet end of the 2.5 Centimeter diameter Vycor tube and boron was placed inside the heated zone in a 0.013 centimeter tantalum foil boat. Hydrogen, dried by passage through a tower of calcium chloride, was used to carry the selenium vapors through the system. At temperatures from 800° to 820° a dark red-orange material deposited at the outlet end of the Vycor-tube. This color did not agree with that reported by Sabatiers and Moissan°a7. The collection of the product was very difficult, and for this reason a new apparatus was developed. 17 §2£i§§.X An apparatus similar to the one depicted in Figure IV, page 12, was prepared. This newer system is shown in Figure V. In this figure the furnace is shown as A. The 1.9 centi- meter diameter Vycor reaction tube, B, which is 66 centi- meters in length, holds a tantalum boat, F, containing crys- talline boron. Pure selenium powder (99.99%), E, is in the 250 milliliter Pyrex flask, D. A 600 milliliter two-necked Pyrex flask, H, has been added to the system. A rubber stopper, G, holds the dip tube in the carbon disulfide, I. After the hydrogen passes through the system into the carbon disulfide, it is sent into a dry ice-acetone cold trap to condense any carbon disulfide that may distill over from the flask, H. All Joints except the one designated G are stand- ard tapered ground glass Joints. It was hoped that any product which escaped into the carbon disulfide would be insoluble in the carbon disulfide and thus would settle out. After a reaction timeof three hours at 8h0°, product was formed. The dense fumes which entered the carbon disulfide did not precipitate as a solid as anticipated. Instead the carbon disulfide turned yellow. It seemed probable that any product which formed would be soluble if any water was present in the solvent. The carbon disulfide was, therefore, distilled to determine if a solid residue would remain. The results will be discussed in the section entitled Results. T— 033. .303? I m .Nm-r Maw-240...... ocawasmad connmo I H Amway xonmm I m noaaopm nonnsm I a Hack anampcma I h azacoaom I a xmmHh Monmm I Q copon moonmnoa< I 0 message I < U 8 A V {\ll.\\’ nu // ii/ 19-..---- V r . >mo SE... 9.00 OL- m «we v um < «Ur-0 so maydsdw< Romy-Mudvm. 19 Serigs XI Since the boron-selenium reaction apparently took place at the surface of the red hot boron, it was felt that an increase in surface area of the boron would be beneficial to the formation of more product. Electrolytic amorphous boron powder of 99 per cent purity was substituted for the 100 mesh crystalline boron used in previous series. The apparatus shown in Figure V, page 18, was used with electrolytic boron, C, in the tantalum boat. At temperatures ranging from 850° to 900°, a bright yellow material was formed in a limited quantity. Upon exposure to air, this yellow solid turned orange and then red. This color change was a result of hydrolysis and indicated moisture sensitivity. The color of the solid material agreed with that reported for the possible boron triselenide product. 20 Series XI; The final apparatus used for the boron-selenium reaction is depicted in Figure VI. The fritted disk shown at G was inserted in the apparatus line to stop the product from being lost. The carbon disulfide trap, chilled with a dry ice-acetone bath, remained part of the system as shown in Figure V. Electrolytic boron was used in this series of reactions along with a 1.7 centimeter Vycor tube for the re- action chamber. The hydrogen gas sweep was increased from approximately ten to thirty cubic centimeters per minute for these reactions. rThe reaction product, as; formed, consisted of very minute, yellow particles which emanated from the furnace as dense yellow fumes. These fumes were readily collected on the fritted disk and isolated by transferring the entire disk unit to the dry box. In the dry box the product was placed in a dried container for further use in determination of properties. The dry box was maintained at a fairly dry level by passing the air through two bubble towers containing concen- trated sulfuric acid and Drierite, respectively. Quantities of phosphorous pentoxide were placed inside the dry box to remove any additional moisture which might enter the chamber. The samples were placed in an air lock at the rear of the chamber and brought into the dry box from that location. Repeat reactions were run using the apparatus shown in HHMIDDV... xmao doppanm I a Hack-asawpcma I b anacoaom I m Mmmam xmnmm I n conon msonmaoa4 I o 0359 noom> I m oomcpsm I < \, Ki / m\ \ , _ SM- ..n.... toe .3222 eat-.3... 22 Figure VI because it was possible to re-run the reaction at least three times using the same boron and selenium. After three such runs, however, very little additional product formed, possibly because the more stable, metallic form of selenium was formed after repeated heating and cooling. The melting point of this form is reported12 as 217° versus 170° for the monoclinic form. The metallic form was noted because of its lustre and its insolubility in carbon disulfide. After a few reactions the tantalum boat became quite brittle and flattened, causing a quantity of boron to fall onto the Vycor reaction tube. As noted in previous runs, (Series II through V) boron in contact with Vycor tubing will react with that tubing causing it to crack. Using this premise, it was concluded that the beron which fell from the tantalum boat was probably not as reactive as that which re— mained on the boat due to the competition for reaction afforded by the Vycor tubing. After repeated heating and cooling under these conditions the boron also exhibited a tendency to cake, decreasing the surface area normally a- vailable for reaction. It was, therefore, concluded that the limitation found to exist on consecutive reactions was due to one or more of the above mentioned conditions causing in. activity of the reacting elements. When in later experiments it was found that the dry box was not sufficiently dry to prevent hydrolysis, a Fisher No. 17-112 Isolator/Lab metallurgical stainless steel dry 23 box was obtained. An argon atmosphere was employed with a quantity of magnesium perchlorate inside to remove additional moisture. The use of this dry box proved very effective by permitting 0.3 millimeter capillaries to be charged with the sample without the occurrence of slow hydrolysis. Final work was carried out using this arrangement. The product was transferred to the dry box while still on the fritted disk. Rubber stoppers were inserted in each end of the unit and it was placed in the air lock. The air lock was then evacuated and the dry atmosphere from the dry box chamber was allowed to flow into the air lock before the sample was transferred to this chamber. At this point the sample was placed in a dried vial, a capillary, or an ampoule for future reference and study. 2% Analytical Procedures Qualitativg Tests I§§t§,§gr the Boratg Ion A. Tumeric paper13 A few drOps of concentrated sulfuric acid are added to a solution containing the borate ion. If tumeric paper is dipped into this solution, it will turn red. Further treatment of this red paper with a solution of sodium hydroxide will cause the paper to change to green. B. Methyl borate test1h If five to six milliliters of methyl alcohol and one to two milliliters of concentrated sulfuric acid are added to a substance containing boron and this solution is then heated on a steam bath, methyl borate will be volatilized. When this volatile borate is ig- nited, it will burn with a brilliant green flame whose intensity is proportional to the quantity of sample present. C. Lead acetate test15 When lead acetate is added to a solution containing the sulfide or selenide ion, the black lead sulfide or lead selenide that is formed will precipitate. Like- wise, if hydrogen sulfide or hydrogen selenide is 25 emitted from an acidified solution it can be detected with moist lead acetate paper which darkens in the presence of both gases. Test for the Sulfate Ion A barium nitrate solution was used to test for the sulfate ion. Quantitative Tests Determination.g§ Percent Selenium A. Method I16 - Gravimetric determination Approximately 100 milliliters of hydrochloric acid are added to no more than 0.25 grams of the solid product and the solution is allowed to equilibrate. Following this addition, 50 milliliters of hydrochloric acid, saturated with sulfur dioxide, is added to the above solution to precipitate selenium in the red form. The selenium is then filtered, washed with alcohol and then with ether, dried at 30° to 120°, and cooled in a desiccator. The cooled selenium is then weighed and the percentage of selenium in the sample is determined. B. Method I117 - Volumetric determination A mixture of nitric and sulfuric acids is added to the product. This mixture is allowed to cool and is diluted to 250 milliliters. A 25 milliliter aliquot is then acidified with 183 sulfuric acid and Na2fiqu.7H20 26 is added. Twenty milliliters of 0.0M9N potassium per- manganate is then added and the entire mixture is allowed to stand. The excess permanganate is then back- titrated with standard ferrous ammonium sulfate to an o-phenanthroline end point. The percent selenium is then calculated. C. Method III - Gravimetric determination Because air hydrolysis of the product results in the formation of selenium, it was thought that a method could be devised based on the hydrolysis of the product. A sample of the product is placed in a dried and weighed Gooch crucible and water is added rapidly. A thin sheet of rubber is placed over the crucible to keep all gases in the crucible. The red selenium thus formed is then filtered, dried, and weighed. When this method proved inadequate due to rapid escape of gaseous hydrogen selenide, the following alternative method was used. The product is added to an Erlenmeyer flask equipped with a cork stopper and a drying tube containing glass wool saturated with nitric acid. Approximately 20 milliliters of water is added to 0.1 grams of product by inJecting it through the stopper with a hypodermic needle. Upon this water addition the product is hydro- lyzed to elemental selenium. Any escaping hydrOgen _se1enide is oxidized to selenium in the nitric acid saturated glass wool. All glass parts are weighed and ) 27 the resulting selenium is filtered, dried, and weighed. This modification of the original Method III also was not useful because of the violence of the water reaction, causing the escape of hydrogen selenide through the drying tube. However, when sodium hydroxide is alternatively substituted for water in the method described above there is little or no evolution of hydrogen selenide. Hydrochloric acid is then added to this solution, fol- lowed by the addition of more hydrochloric acid satu- rated with sulfur dioxide. These additions, as given in Method 1, page 25, precipitate the red form of selenium and prevent the escape of hydrogen selenide. The red selenium is filtered and weighed. The tared drying tube is also weighed and the percentage of selenium is determined. This modified gravimetric procedure will be referred to as Method III, alternative 2. Determination 9§_Percent Boron19 The sample is weighed and placed in an erlenmeyer flask. Water is added to the flask to hydrolyze the product without regard to the loss of selenium as hydrogen selenide. All red selenium which does form is filtered and mannitol is added to the filtrate. This solution is then titrated with standard sodium hydroxide 28 to a phenolphthalein end point. The percent boron is then calculated. 29 Measurement of Physical Properties Melting Peiut Detegmiuapions Heated pagh teeunigues The yellow product samples were placed in dry Pyrex ampoules in the dry box. These ampoules were then evacuated by means of a vacuum pump and sealed immediately in the hot flame of an oxygen-gas torch. After the ampoules were made they were placed in various hot baths to determine at what temperature the sample would melt, but no melting had occurred at a temperature of h80°, the maximum temperature at which it was convenient to use a lead bath. Iflhfi {urnece technigue Since the melting point was higher than could be determined conveniently by conventional bath methods, a tube furnace was used. The solid product, sealed in a quartz ampoule under vacuum as described previously, was placed into a tube furnace. The temperature was raised slowly so that the sample could be examined at 5° increments to ascertain whether any melting or decomposition had taken place. This procedure was followed until melting or decomposition was noticed. This temperature was measured with an iron-constantan thermocouple. 3O eregmiuauioulef g-zay Eowge; EELS X-ray powder photographs were obtained using a Norelco 119.6 millimeter diameter powder camera and nickel filtered copper KIX ()\ unres tative guides. The 0.3 millimeter capillaries that were used : 1.5h18 A) radiation and used for quali- were centered in the camera and exposed for times of one to four hours. Although X-ray powder photOgraphs were taken of both forms of the product, only pictures of the crystalline form could be obtained since the amorphous form gave no lines. In preliminary investigations an ampoule which was previously filled and heated was placed in the X-ray beam and the recording of a diffraction pattern was attempted. By this method it was proved that the heated form was crystal- line and the powdered form was amorphous. Accurate photo- graphs were not obtained because the large ampoule could not be centered in the camera. . In an attempt to correct this failure to center the ampoule an internal standard was added to the ampoule. Since the number of lines for potassium chloride were few, it was selected as the standard. If the product lines and the potassium chloride lines could be measured accurately, a comparison could be made. This comparison could be made accurate by plotting known "d values" for potassium chloride versus those obtained from the distorted X-ray obtained for the potassium chloride in the ampoule, and transposing the product lines to give their true values. 31 Determination of Infrared Spectral Data Three methods were available and each was studied as to its applicability for use with the hygrosc0pic product. Pegassiuu pgomide pelleu EEEEQQ The product was placed in a small amount of dry potas- sium bromide and mixed thoroughly. This mixture was placed inside a Perkin-Elmer potassium bromide pellet press and the unit was evacuated while pressure was applied. After three minutes, a pellet was removed from the unit and placed in a holder. The holder and pellet were placed in the samplebeamof a Perkin-Elmer Model 21, Infrared Spectrophotometer, and a spectrum was obtained. The disadvantage of this method was that it did not prevent hydrolysis. Selvent ueuueg A small amount of the product was placed in dry carbon disulfide. This solvent was dried either by mixing it with phosphorous pentoxide and allowing the mixture to stand for twenty-four hours, then pouring off the solvent, or by dis- tilling the carbon disulfide after the mixture had stood for sixteen hours. The carbon disulfide containing the sample was placed in a special holder designed for liquid samples. This unit was placed in the sample beam of the Perkin-Elmer Model 21, Infrared SpectrOphotometer and run against a control sample of carbon disulfide in the control beam. A spectrum was obtained. 32 Miueral 9;; uu;l EEEEQQ This method entailed the mixing of mineral oil with the product. A few drops of this slurry were then placed onto a salt plate. Another salt plate was set on this first plate and the two were rubbed gently together to spread the drops into a thin continuous film. .This set of plates was then placed in the infrared spectrophotometer in the sample beam and a spectrum was obtained using air as a standard. In initial trials sodium chloride plates and optics were used in the Perkin-Elmer Model 21, Infrared SpectrOphotometer, but on final runs cesium bromide plates were used in con- Junction with both cesium bromide and sodium chloride optics in a Perkin-Elmer Model 221, Infrared Spectrophotometer. Since the samples were dispersed in mineral oil and the plates were prepared in a dry box, little hydrolysis occurred during plate preparation. The dispersion of the sample in mineral oil also inhibited hydrolysis during the run. 33 Determination of Solubility Data Only limited trials were made to determine solubility data on the product. Samples were placed in hot and cold water and also in freshly distilled carbon disulfide, pre- pared as previously described on page 31. No exact solu- bilities were determined; only if the product was very soluble or Sparingly soluble. Reaction Between Boron and Tellurium The apparatus shown in Figure VI (page 21) was used. Tellurium was substituted for selenium at E. Electrolytic boron was placed in a tantalum boat inside the Vycor reaction tube. A hydrogen sweep of approximately twenty cubic centi- meters per minute was bubbled through the tellurium. The tellurium vapor was passed over boron maintained at 10500 for three hours. RESULTS Sulfur-Boron Reactions In the reactions carried out between sulfur and boron, Series I-VIII, a white powder was obtained. Qualitative tests were run on this compound, but no quantitative data were obtained. A positive sulfide ion test was obtained using lead acetate paper. When barium nitrate was added to an acidified solution of the product, no precipitate formed. It was, therefore, concluded that the sulfate ion was absent. An acidified sample was also tested with tumeric paper to test for the borate ion. A positive test was denoted when the paper turned red in the acidic solution and changed to green in a sodium hydroxide solution. To verify the tumeric paper test, the ethyl borate test was tried to determine whether or not the borate ion was present. The appearance of a green flame, upon ignition, gave positive indication of the borate ion. X-ray powder photographs were taken of the white solid product and compared with a boric acid control photograph. These proved identical and it was concluded that the sample was hydrolyzing in air according to the equation: BSx 4 3H2 H28 4 H3303 + 2 x H2 When the material was placed in waten a violent reaction occurred with the evolution of hydrogen sulfide. The vio- lence of this reaction was reported by Sabatier3 and Moissany 3h 35 when boron trisulfide reacted with water. The positive borate and sulfide ion tests on the white solid product indicated that a reaction had occurred. The X-ray data proved that boric acid was formed upon air hydrolysis. These two facts plus reaction conditions reported by Sabatier3 and Moissan1+ led to the belief that a boron sulfide had been formed. 36 Selenium-Boron Reactions The reactions between selenium and boron, as described in Series IX through Series XII, eventually led to the for- mation of a bright yellow solid. The solid formed in Series IX, page l6,was undoubtedly contaminated with red selenium, which had been carried through the furnace. In the subse- quent series, however, a dense yellow cloud emanated from the reaction chamber. The minute particles which formed this cloud were trapped in the apparatus of Series XII, page 21, and studied. The attempt to trap the solid product in carbon disul- fide (Series X, page 17) proved ineffective. No precipitate formed in the solvent, but it turned yellow, thus denoting the passage of a foreign substance into the carbon disulfide trap. When this discolored liquid was distilled to isolate the product, only a red material remained. This red sub- stance turned metallic gray and formed a mirror-like finish on the distillation flask. It was assumed that this solid was selenium, and denoted either hydrolysis of the product or direct passage of selenium vapors into the carbon disulfide. The substitution of electrolytic boron for crystalline boron (Series XI, page 19) led to the formation of a yellow solid in the outlet portion of the reaction tube, but the carbon disulfide in the trap discolored as in the previous experiment. The quantity of yellow material which formed, 37 changed to orange and then to red upon exposure to air. This color change was accompanied by the evolution of hydrogen selenide and indicated possible air hydrolysis. When the carbon disulfide was distilled, a small amount of selenium remained as before, but a second substance also was present. A positive borate ion test (methyl borate test) on the second substance, along with the formation of the previously mentioned yellow solid, indicated the passage of product into the carbon disulfide. A sample of carbon disulfide, which had been dried for twenty—four hours over phosphorus pentoxide, was substituted for the non-dried type. The product did not precipitate in this dried material, thus denoting its extreme moisture sensitivity. When the carbon disulfide was cooled to dry ice-acetone temperatures, a solid formed which, when dried, gave an X-ray powder photo- graph; which was identical with the X-ray photograph of the hydrolyzed product from the boron and sulfur reaction and the boric acid control. The apparatus of Series XII, page 21, proved the most effective and the product formed by this technique was studied thoroughly. Following are the results of these studies. 38 Characterization of Product The yellow solid formed in the reaction between selenium and boron using the apparatus of Series XII, page 21, was checked qualitatively and quantitatively. When a qualitative borate ion test with tumeric paper (see page 29) was conducted on a solution of the product and a solution of freshly precipitated red selenium, each gave what appeared to be a positive test. A methyl borate flame test (page 2%) gave a positive borate ion test on the product solution and on a boric acid solution, but gave a negative result on the red selenium solution. It was, there- fore, concluded that the flame test was the most sensitive for borate ion in the presence of selenium and that the product contained boron. A positive lead acetate test (page 2%) on the product indicated the presence of selenide ion and coupled with the positive methyl borate test (page 2%) denoted that a reaction had occurred. Quantitative tests to determine percent of selenium in the compound were then conducted using the vari- ous methods described in the experimental section (pages 25 to 28). Following are comparative results using each method: Table I Quantitative Results of Percent Selenium in Product Method e n Seleuiuu “1"" " 67" FRI" E II 27.0% III 67.2% 111-1 760 0% III-2 91.02% 90.90% 91.87% 39 Methods I through III-1 proved ineffective and gave low results due to the escape of selenium as hydrogen selenide upon acid and water addition. Method III-2 proved effective when samples weighing approximately 200 milligrams were used. The substitution of sodium hydroxide in this latter method for the acids used in the other methods also prevented the esdape of hydrogen selenide. Three separate determinations were, therefore, made using this method. Two boron determinations were made following the method described on page 26 using 0.0858n sodium hydroxide for titration. The results showed 8.51 percent and 8.77 percent boron in the sample, compared with 8.36 percent theoretical for boron triselenide. The results obtained are somewhat high due to overtitration of the mannitol solution. The end point was masked by a slight discoloration which resulted from suspended red selenium which passed through the filter. The average percent selenium obtained from Method III-2 was 91.26 percent. This value was compared with those of 91.6% percent for the compound formula 32803 and with 93.03 percent for the compound formula HBSea, another possible reaction product. The average percent boron, 8.6% percent, was compared with 8.36 percent (BZSe3) and with 6.37 percent (HBSeZ). Both the percent selenium and the percent boron compare more favorably with the compound formula 32893 than with the formula HBSeZ. Therefore, the yellow solid was assumed to be boron triselenide. MO Melting Point (Decomposition Point) When the boron triselenide was heated in a sealed quartz ampoule in a tube furnace, the sample was noted to decompose at 556IS° into a metallic gray portion and a red substance. At 800° the metallic portion glowed red, but did not melt. A new ampoule was therefore filled with more boron triselenide and placed in the hot furnace with one end of the ampoule at room temperature. Using this technique, it was possible to distill the red substance to the cooled and of the tube. When the ampoule was broken, a positive selenium test was obtained on this red substance using the lead acetate test. It was, therefore, concluded that the black solid was either boron or a lower boron selenide and the red material was selenium. 32893 ~-———s>——- 2B 4 389 328e3 —____;>—— ZBSex 4 (3-2x)Se During the melting point determination studies, it was noted that at 195° to 235° the yellow powder form of boron triselenide changed to a more compact solid formation with a darker color. Infrared spectra and X-ray powder photo- graphs were taken of these two forms to determine if they were similar. Because of the high decomposition point of the form obtained at 195° to 235°, and the known covalency of boron oxides, it was concluded that this form was at least partly covalent. #1 X-ray Powder Data In the original qualitative tests, the product was placed in the capillaries without the aid of a dry box. When these X-ray powder photographs were compared with ones taken of boric acid and the boron-sulfur reaction product, they proved identical. This proved that the common hydroly-I sis product of boron triselenide and the boron sulfide was boric acid. Such X-rays were used as guides to determine the presence of product. X-ray powder photographs of the yellow powder form in ampoules resulted in no lines on the film, while the heated product treated in the same manner, gave many lines. These lines were not accurate due to the inability to center the heavy ampoule in the camera. It was, therefore, concluded that the material as prepared was amorphous, but it became crystalline after heating to 1950 to 235°. Since no decom- position was apparent, this product was assumed to be boron triselenide. Attempts to use potassium chloride as a standard in the ampoule with the heated boron triselenide product proved futile. In a series of attempts, either all potassium chloride lines or no potassium chloride lines were evident, thus showing the need for proper mixing of a critical amount of potassium chloride in the ampoule. This series of attempts was abandoned upon the acquisition of the Fisher Isolator/Lab metallurgical stainless steel dry box. 92 By working in this dry box in an argon atmosphere and using standard 0.3 millimeter capillaries, good X-ray powder photographs were obtained. These photographs were read and the following "d values" calculated from the Bragg equation, n>\= 2dsine, whereix.equals the wave length of CuKd radiation, 1.59183. Table II compares the observed "d values" with those of cubic and hexagonal boric oxide. Table II X-ray Spectral Data, "d values" Hexagonal 3203b Cubic 3203b Observed 325e; 3.75 6.08 6.77 3.92 9.11 2078 3080 3.90 2.230 3.78 2.165 3.21 3.26 2.096 2.92 3.10 1.920 2.60 2.82 1.872 2.A9 2.6h 1.822 2.36 1.710 2.26 2.30 1.659 2.16 1.522 2.09 2.11 1.918 1.98 1.903 1.39 A comparison of values led to the belief that the heated boron triselenide is not like either hexagonal or cubic boric oxide, but that it was similar to the cubic form. The "d values" of boron triselenide, as noted, contain values for a triplet and two doublets, or alternatively, for four doublets. If these triplet and doublet values are considered as single lines the comparison to the cubic boric oxide is b. Values from ASTM X-ray diffraction card file. “3 more pronounced. It is reasonable to conclude that if selenium atoms were placed in a cubic lattice similar to that of boric oxide, the difference in size between large selenium atoms and small oxygen atoms would distort the lattice to a degree that would cause splitting of X-ray lines. These data are not conclusive, but tend to point toward a distorted cubic lattice for boron triselenide. 9% Infrared Spectra Data Of the three methods described in the experimental section (pages 31 through 33) only the one which used mineral oil proved useful. The moisture sensitivity of the solid boron triselenide made the use of potassium bromide pellets and solvent techniques impractical. In both cases bands comparable to those reported by Miller and Wilkins20 for boric acid were obtained. These techniques substantiated X-ray data which showed that boron triselenide hydrolyzes into boric acid upon exposure to moisture. The first attempt at making a mineral oil mull was unsuccessful, producing a boric acid Spectrum,because the mull was not made in a dry box. In all subsequent tests, a dry box was used and spectra were obtained for the amorphous and crystalline forms of boron triselenide using a Perkin- Elmer Model 221 spectrOphotometer. Cesium bromide plates were used with a sodium chloride prism in the 15 to 37 micron range. After the spectrum for amorphous boron triselenide was run, the plates were allowed to remain Open in air for 1.5 hours and another spectrum was obtained containing boric acid hands. This displayed prOper dispersion of the sample. Table III gives the results obtained on the amorphous and crystalline forms of boron triselenide compared with the results on boron sulfide obtained by Greene and Margravelo. 95 Table III Infrared Bands - Amorphous and Crystalline Products Amorphous B28e3 Crystalline B28e3 B283 1372 cm-1 1300 cm'1 1322 cm-1 1250 cm"1 1150 cm'1 990 cm"1 837 cm'1 919 cm-1 611 cm-1 859 cm-1 580 cm‘1 602 cm"1 The values for amorphous boron triselenide were obtained by running the spectrum of the product over the entire 2 to 37 microns range and are shown in Figures VII and VIII. Figure IX shows the same sample from 2 to 15 microns after 1.5 hours in open air. The values for crystalline boron triselenide (Figure X) were obtained only in the sodium chloride region, 2 to 15 microns, to establish the similarity to the amorphous product. Shifts from 1372 cm'1 to 1300 cm-1 and from 1250 cm-1 1150 cm"1 are noted when going from the amorphous to the crystalline form of boron triselenide. These are large shifts but are apparently allowable when one is working with polymorphic substances. Much investigation of various crystalline forms of minerals had been conducted. Hunt, Wisherd, and Bonham21 made a thorough study of many such materials. Among the results given by them are various infrared data which show differences in Spectra between the crystalline forms of inorganic materi- als. One such example was the comparison of spectra between quartz and alpha-quartz. Absorption peaks were obtained at 7.3, 12.2, and 19.2 microns for quartz and 9.2, 12.8 and 19.9 microns for alpha-quartz. NO. (:21 ‘ GAMI SUPPRESSIO SCALE J/C SPECTRUM No RESOLUTION 92 . RESPONSE MO .3 SAMPLE REMARKS P .ISM SPEED /5 I...«‘ . _. . L- ‘ ico ,/G NORWALK -CQRP; .PERKMtELMERt I I I D iTHE .e-h , .4 . . IIII-IIC . v....l .. 1 .r _ u «1.. 1 -. I-. g. divans-Irw- a A . .II-II-JI-I-I-I :I, . . ‘ L-.. -L-I_ II.I-III-IIIIOI I _ _ m . M I « :1 . _. III III I (III __. m --._._.._.'._.-_..__. .- . I « 1.0.0!!!" .Illfl‘lti - I v I I I I . -—-——I——~—- _._- . . 44+. . . V4. 1 , .Ie . 4 . . . 4 . .1 1 4 . .7 44 . *-4 n 4 4 . - I . t ..f . 5-4 .17 ....4 r4 .. .1...» I 4.. . _ . . v... .. I . . 4 p. . 4 I r . o o ._4 a.» 41¢ 9. 4 4 . _ . .. .. c . F q» o a . . 4 I a 4 . c . . . -.. . - i L _ _ . _ I e .v . , i < 4 a 4 a a“ 4 V- 4-. . _v . .4 4 4 J 4 an r . ,. . . . . . . u . _ 1 . . . . I . , . . 4 . I . r4 . 4 . . O .4 .. . I . . 1 . t f. T . . _ . . J .L * . t v1 ‘. w q 0 .4 1.? . - I . .I 7! V I b c 4‘ 4. 4 c I 4 n — u-v V 7¢ . Y . 1 . ......... 1,. ..... . _ . ; . . . .I III-+1 l a 4 . . . . . . . . . a 1110 All! IIIIIIIII-ITIITJ'IIITIIVl-Ouie't 9 v III l4II4Ix-lIIV'I.I¢ A 45.9.1414 .0..-u| . . 2 _ . . r 4 . - . . . . . . . a . ..... 21.44.44... I. ,_ ......... t prev 3 5 +5 34 4 . 4 . . . . . . 4 f n c . _ . . A . . a a . . a . .. .I. .v 4 u. . e . . I . . JI VII-III -IIiIIIl.|IIIII-I.I .v 1.1-91. i l IIIIII _ . . . . . _ ...... . . _ . . . . p v a o v V .I .I III IF III. IIIVJY-IIIII .9 .0 +|IIII .IlrlI . . l r . . . 4 i 4' . . . - . 1 . . . - . . ......... . 33 .-.. I-II. flu , o e - b r c . .41.... 4.. n.4,... Y.-II-II7I+-I‘II-III -.-Ilv I-I-L VIII _.....1..,_..._+_4..1-....b..4 . . 1 . ,:O-I- 32 ...... ;- are . " +701“? i'MWPI's 47 o .:.:3——-o—-o~— ~-——---;— .1..._.._ 1» I I. 1 T J I II I 11‘! - o I VIII-I.- III II . I Ill-'11.! OIIII I. '0' . I‘I II‘l'l-Jr» é. iIIIOIIL 90 . d 0 5O 4O 0‘ O 10 O ! 28 [III {III til-I IIIIIIAY-A OI IIIIIIII’iIIII-II- 4| I- .IIII ..II\|II.I|J I Y T I 1 I _ 4.-...- 4-... 444 411-....4. -‘ I g : . . L...- ..-.-.---.-.----- -13.. I 27 1 I | 9 I L I T L I l I 7 I I I -. 44...“-.. 3,. ..._,_.__ I I 7 I I —‘ ~—+ , i . I . . . . _ . . . . . a... J I.--I.-.:..--- . 1-2. _-.-..- ------- , . . -43- -. i. 4 26 4 I— — - I 1 .,_.A,_._..V___ II I. -.9Il-I_I. VIII-IIIIII-III‘IIOIIIAI .I {I‘ll-9.1L: 90 80 1‘2. W70? 60 50 I T-IY . II {QIAT I210 23 ‘IIII IIIIJ 6-1! I'l‘i-l-l'll .ILvI II-.Ilv! I. O IIV-IYI-Il fle'oIII-III. il‘ni‘i.‘lfl|a..I-I- 22 II-IA'II.II. 4v .I. I.Il-II|-. I'll-.1 t-II ii.I-.4YII-II -III|III I 1 I ) I 4 _,._,_, I I I I I l I I I i L i i , I I I I .. ,. .- 4- 444..-..4 1 2| m r I .... ‘A I.-.IIIiII-l-l-IfL-I-Is41; - -1 I I J . i l t‘°" l I I O l 60 Saga: 2:: LIE§<9:-~ .1 O 30 l 2.0 10 0 20 l I I 1 l I A. I I I F I l , I I 6 a I... I -II V - -1.- 11' I9 . . . - . , . -444 4- I - - . . - 4. . 4 . . . . . . . _ v - . - 4 . a A. . . . . . . . 4 _ . . ‘ . . . . . . . . . r III-o! 'Iillv- III,- éI-s III... III-I'LY- .- I. .ql . Av iIlPIIII..III--II.Ii IIIII.I 1.11 I‘ll-III.) \rliIIOIII I I-lIu I r . - - - II- . 4 . 4 . . . 58 I I TIIYIIQ IrItILr-ITI: nIIIITLv le-lv- 191.9.- I ilk- ItI-VL - Iv .{II-Il-Irt-IYIIIII I III. ill-I- . I It 9.41- LI Ol-III-‘iII-IIII- .I -II41I[lJiI-..II-l-II.17111i-i4 Gas - BY AIM I ’70 F I i m Suppression 17/ Source AGC OFF Exponflon on: y {X Inch X [.3 AMP .444.-.4_._... - l _. Cs Br Prism PP Spectroscopy Laboratory MIdiand, M-ch mm °/o SW o W CORNING CORPORATION 000 2x Gain sI-F‘\~~- \ch A"en-Inter //0 0 F81 Date 7/20/5 C" Ident. b: {(3 F . .mm 94/7? if» 50 )1 mm Lab. No. No. D ReF. v D 4-. 4... 44 4 . . 4 . . . - - .. 4- - . . , . . . . . . 4 . . I I III. I. I _ . . .. I . 4 . I . . I41. I4 I I I I.I-TI .~ I II 4 Ir rITII4III II4II I. .rIII II II I.. 4 - . I.I . . - I . I .I . .. . 4 _ . _ 4 . I .r I . I L I I I. .II. II . v . . _ . - 4 . . . . I.I I ..I II II. .| . . I4 .IvI )4. ..II r . _ 4 - _ _ . _ 4. I d Ilfl-III r . . . . . . . .. I I .I o I I I . I. I 4 . . . 4 - r . 4 - ..T. . .. .. .. .444 4 _ . . _ I . I.I-II... ,4.- . . 4 4 r .f I I v... I» L 4 _ ..r . _ 4 4 I . , . I. 4 _ . _ .4 .I- 4 I. I.- .-..wTINI I.I.II. . . _ I I.. I74 I I. . . . . I . II .A I 4 4 4 I . _ . . . . . ..I. . . .I. .IILII I . . 4 _ — . - . - - . - . . _ - I. N” . 4 l I I I I I I I I 4 .. I .- .. 4 I l 4 . I I rI | I | ‘1 I I I I -I I I l ‘I I I I ‘ I -.-I I I— P—-y -- 0L" ; l_,_ K.“- I ., .-. l..— I I I I y I I I -44 I I I-I / I '7’ I I _I ‘1 I I 4 I . - I I O- I I . I I I c. .— ~- ‘ I l , . I—. I «Hr-h—r ,I ,—-I I I I I I .I _I_ I Y I A ‘1 l I L_._..._. I’" I ,. I I I I fab . l 4 || '1 ... 0‘ 4 4-. I}- :-I 'V‘ >—I- .-I—4 H. 4 IT ,. - _ . - . . b. I - - 4 - .. - fN . . I. . . I I . . . . - . _ . I o I r v . I 1 I 'I I I 4 . I I . I 4 _ . _ _ . . . I. I I .4 I . . . . . I. I 4 I I I I . 4 .- . I . . A I H I III) . I rIII I n . . _ . . . 4 4 . - . .. . _ I_ III . I .. I P I .. I - . .I .I . . . _ . . I I . II. . .I I p I. I I I . I. I I - . . v .4 I. 4 . . . I . ...I . . . . P _ _ fil- R I]! TIIIIIIIIIIIIJI III-III ILIII I.- II II II I _ . . . . . 4 . . . I . . 'lll IIIVL’ II I If II‘IIIIPII . . - All, I ll; . I. -I , I .IIII Is- _ . - . . 4. . 4 I4 - . III. I . _ O . _ l I 4 I . Q 1 I 4 W _ C I I I I I I. II . I I I I . . . II ..-I I I . . . . I. I _ . . . . . . . 4 II. rII IILI..I. III I . I . . . I _ _ 4 I I I I l I I I . . '- . ... I.I I I 'y . I—I 1" THE PElRliKlvN-ELM . I > I I I I -I 4 I I Il'IIIIlI-l] I I I I I I I I i I I I r4_ I I _ 11 I I I I I I I I I5 L I I 4 I I I I I I ;Ii .I d» 4 7‘. I «A ‘ I ‘-9 I I I l. I I I I _. I l I I IIIII IIIIIII.I.I.II..III III I.I...Il I T l I I I I I I . . \ O I I 1.4 I I I I I I I ‘I IE? or er II: II‘ O I I I A I I 5.6 I . O I III-I - 4 ..... - -..I----lI..I- -I-. .. 4 -._. 4 4 _ . , .- - . . .- . _ . . - I 4 . . III--III-I.II--II.II I.III LTI-I -I . IJII . _ .. -4444 -.. - - ..- .- _ . . .- ..I- -.: | I In .I II. t v I I _ ‘ . . . . n _ 4 _ I . 4 . I.” II. .-I . . k . . .I .4 It... .I .I 4 I. . .- . 4. . . . 1.7.. .. .I.. . I. IL-.- . .- I . . . . . . . . - _. ..4 -.. I. . 4 _ . I. . .... I . ..-4.-. _ 4 4 I ...I I4I4-I ..I . ..I, .I 4 . 4 . I . II4I +1. I. I 4. I . . . . _ _ . ; I I I . I I I I» ...II .- 4 4 .- I . . 4 ._ .- I. .. .. . I 4 . . 4 - 4 _ . L. . 4 4 . III-I III. I4 I .II . I 4 . . . . . .-_T I I I .. . 4 4 ..II..I-- IIIIII.I :- 4 4 4 . .4. - ..4I.... . I I _ - I IIIIIII III-I --I . 4 . 4 . . . 4-I . - 4 4 4 - . I .I . I . n I r I I _ . 4 _ _ I _. . 4 I . . . . I III I I 4 I . I I I I .I “IIfi . . . ._. . . _ - a I-.-I. 14 4 4 .. I . .4. . . +I. I . _ 4. . 4 - . . I 4 . 4 4 _ .r 4 -. .I.. . . . . . ..I.» . .I.- . 4- _ .- 4-- . I - .- - . . I - . . _ - 4. I. . .. . . -. .. . . . - _. 4 . _ --.. II I. IIIIIII IIIIIII I IIII III-.I.: I .II III I I III». II.II.II II IIIIIIII III .Ir _ I c . I 4 I9. 4 . I .4 II I .1. ... . ; I . v 4 4 .I. IIJII‘IIII' III I b _ Y I _- . 4 . . . . . . . . 4. . .. . .. . II.- _ . I I. I . a I . I I . I A . II. . 4 .. 4 I I I. I I I IT 4 III I I IL . ...4‘44— «444 ,4 I .. . . . .- '4 . I . . I I . I I . . . r I . I - II -—- >4 4-4 -44 4 4-444 444.44-44 I I I I I l I I I I I I I I i566 50 " .4 ., . - - 4 4 . - . _ , - -- -_ I I I 4 . 4 . . . . ...4 ..4 I 4 I .41 4I.II. I41 . 4 . .4.. 4 . _ .PII .IIII. II . 4 4 . . ... .- 4 . . _ . I I _III._ 4 . 4 _ , 4 4 . . _ I II I .I . o v. I4 _ . .4 .‘ ._ M . .._.- 4 ... . . -,-;-I. - 4 . - . _, - _ . . . . . I I . 4r 4 ... .4 _ . . 4 . . 4 4 .. . . 4 . . ... . . . . 4 - 4 - - -. - . .- .- - .. II,I.- - L 4 . 4 . _ . .-. , .. ,._ . I::- . . . . .. -. -.--4 I - 4- --..-I.II_, ,4 . 4 , . 4 H . .37.. .45... I I U I I I III. II4II. .I.". III 4 I . I I.I+ I .I 4...] I . . . .4244. 44 40. _4._44 .4. 4 44.44... 4.4.4 _. . _ I .. I . _ 4. I I I . II III I I. I IIIIII I . 4 4 _ . .4 - .- - . I . .4 . I _.-.I . .- _. . fl 41 _ . I_ L 4 .4. . . _ 4. .. . . .... . - _. - -- -. - ,. -I--.-- 4 . _ ... 4 . 4- - 44 .. ...I 4 4 4 ». III 4. I . .4 I tn I I I I IG I. I _ 4 4 . . . .- . . .4 4 4 . 4 . . 4. I . I . 4 . . v I 41. I I. . 4 ..4 4. - .. . 4.. -.- . . 4 4 . - 4.-. - - .4 -. . - . -.. ..I. 4 .4, 4. _ . 4 so '40. 444 44 . 444-_.. ( I , - ...—44444-4 . I . I- .4 4. 4 444.4 I I I I I 0 I v I T , 4 4 4 a _ 4 4 . 4 I .... --. I . -I. . . 4- .. ..I. -I.); 4 . 4 o 4 .I I . 4 4 _ _ _ 4 I. ...I. .-.4 .. I .II -.I... . - . -. 4. ..- .I .. . . .I-”. .- . - - . _ 4 4 - ..,444. 4.4.4.4.. 4 I 44...-» __4_._4 4 . 4 .. . . - . .4 -.----.... 4 I p . 4 4 4 . 4 4 . . . . . 4 I . .I I- . . . . III.I 4 4 . . 4 . I . II . I ... . 4.. . 4. I . . I II ..I- . . I .4 . I- . . I. I 4 4 4 4—444 4 I I I 4 4 .4 . .4 .. . . I . I . . ..II. . ..I I: .I l 4 . . . _. .4 . .- 4 . -. .. ... ... ..--.--- ..I. 4 _ . . 4 .. I.. - 7.; VI I“ III . 4 4. I . 44 4. 4 . 4 .. . .I. . . .- I41. 4 4 . 4 .ge-.W.. 4. . ..‘...- - Inu _ nu I. nu _ nu .-4 .AV , . . my 4, nu - ... nu . . ..IIINV .4- I 4 .1 4 a .4 44 e 4- 4 q.. 444.-.I-.-; II . 4 . . .- .- . I: .I.- .- . .. _ 4 .. _-4 u . -.- .. -. .I. . I4. 4 . . - _- - .-...:.....- 4. _ . . _ 4 . - .- .I-I. --_I . II. - 4 - . 4 4 _ . m 4 . . ... . I . I 144-431 I.. 4 j . . 4 . . r . . ... 7...”. .r . II ,II _ __ I.I . 4 , . 4 . . _, . .2 .. H.» . mwg- . ...—4444444 --——. _ 44—4 '- l L \ l .4 44-.— -.-——-4———- ——I—44 .44 -..-- 4 -—~. _.4 I44 4, -4-.. I. -444 I I . I . I I 4 I . . I . I . I I . I . I I . I I 4 . 4 __ . .. _ . -. .I.. I I . I . I . I . . I I w: . . . . 4-,. - . M - .« h --: .- . . . . - I II...IVI4.- -- -4 .. ...-I‘ll; , 4 - . ,. -. ...4. -. .I a . .. I . . . I I . . . . I I.I . _I ‘- I IIIIII IMV In ”IIIII t HI! A . . . - . . . . .. . . . I . .. .I. . . . . - . . - . - . . .I... . I I . . . I. I 4 . I . . I. . . . .I4 I . . T. v _ . . . I I. . - . . . I. . I I -I. . I . . . . . 4 HI w o v I. o v I I II I .4 . ... . . . . . . I . .IIIII I4 4 . . ....III I; 4 - - _ . I. 4 I I I . I .I I. I. ..III. _ - . - . -. ..- . . .1 4 . 4 . . - .. 4 . I . I . _ ..I. I I. .I_I4 . P: . .... ....... 4. . I. . . . . ._ -.. - - .- - . --.-_ - -_I4.I 4.1 _ . . ._ - -- - t. ,- ..I. 4 O- O O O O O - o. 0. IO... _ 40 7. . 4 6 5 4. . 3 . -- 2 I. . .. I - . 44... 4 4 . .. I . . ..- . - . . - I .. . . _ . . .. . . . . . . . .. - 4 _ 4. I. _ _ - . . I. I ..I- . . - - pIg . . I . . - - . .. - 4.2II . I I . .I.- I I I .I 4VI_. I I.I I I 4- .4 . . _ .. ..I. .4. I . ...: - I - -I - . 4 . 4 I . . .I I I»: 4 II..4 . .I. . 4 4 . _ M I . v I I I . 4 .- . . ._ I - -. II 4 _ 4 - _ . 4 4 I. . . . L .. -. . - 4 4 _ 4 . . . - , 4 . . .I - .- .72 . . 4 III-I4! . 4 , - .I . I . - - - ..I _ - 4 . . - 4 . - . .I. I. . .-. I.Ir- _ - 4 - - - . .4 - . 4 - . . - . - I--- , . 4 1 - . - _ --I- 4 . 4 _ .44 4 . 4 4 I I 4 I I . I 4II .. I .III .. III4I. . . 4 4 - 4 . . r . .L.-.4.II ”I; ._ . _ . .. . .- I.I. 4 . III , I _ - . . .... . - - .- . .- I... .I. III. A . I V . . .I . . . I . I 4 4. 4 . . . I .-. 4 OH: 4 O O , 60 O:- .O. .O... _ . . .- C ... .4 3 2 1 _ O... , ..I . r I . 4 . . -I.--- . 4 .1.-. 9 4 8 .7 _ . . , . -: . 4 _ ,- - - ...-._ .4 I II. . - . - . . I . .I.. . -- . w . I 4 4 . I Iv .I .II I I- I + II .wt..r.I . - . 4 - - . . . - . I, . .. ..- . I . I I . I I .II. IIA I . 4 . II . - 4 . .I . . . . - . 1.. W 4 I I I . II I ...... I M _ . - . . III 4- .IIIIII . .7. ;I I 4 I I. I . I I I A — 1.45 .I . 4 . .- 4 - . I. .I.. -. -I . . _ . I I I I. . I . . I I I “.III III... I 4) IIIII _ 4 I I I. I.I-I. II-I. . . 4 a < . t I t . I I'I. I I I 0 III I I . . . - I - - ..-- - .I-.I-+-II I: ...I-1-..... . . .. . ... A f. .- .P......-.-;.-I ...-U. I--. .4 . . . . . I . I . .I . II I I . I _ ... . II .I I III-III . . . . I. — l 4111‘ o I v' «I 4 I IN ~ I4 ‘ I u i I v I. . I . . .... I. ... . . I4 . . . . . I4 . I. ...I III .I. I . I I . . I V . I I Y I III .I . r -I I I . III-II,I4I VIII. I4 I I . 4 4 _ . . I I . . r. . I .- IF I I. I ... .. . . I I I. I ._ . I. .. I I. .. . . 4I. I.IIIIIi1 I, . ..-. -. . -. .- _ . ... .4. 1411......» -- . . I I I. I .I .. . . I . L . . \ II. II II II_I\ .7 ...III. -14 I I I. wI.I . ON :02. .O .O - -..-O .-.-0-2...-0- O. O .O. OI... 4.0 6 _.5-._ 4 - 3. .-.2-..-.4--I_.-: - _ 9-. .8 . 7 . - -_ . .. .1!- I I. . - .-4 - r . . . 4. , 4- - .- - 4 ...-I41 I I .. ...I . _ .II .I .41... - ... 4.. .- .- _ -.I. ..I . . . .-_, . . - , . - . . . . . . . . -. . .. -. - -. . - - r. . . .---.I....- - 7 T I.- . - . - . .r- . - . . . - 4 4_ _. . .. 4 --VIHI... .. II... 4 .. _ I [I v I I II ..II «Ilfl I . Y. 4 .. I44 . . I I I I .I I I. I I I II I I I I _ I I I I II II I I . I I I I n . . . I .I I . I + I4I .I II II I? ..III ..I .- III . I1 I I .- - . - . . . . 4-.- I.. ..-.I-I-_ I4.- . 4. .. .-.. . - I444- .41. -I-.4-...--...-.-..... 4. .- - .. .. - 4 .. . - - . .I.-l4 .. - I“ 4:; I .-. -. .- I... 4-1._4-._-I.I..I:4 .... - . -. - -. .. . . .. I -. -. . .- ..- . 49 FREQUENCY (CW) I A. w ., _ m . A .A «A ., A . .. F #I $-44. . f. f III-_1I.Ir A.“ .IMLIPIII. — ”I.I ._ MI. . I. I, F u . ... I --I . r 1‘... .1 .- r_,I_I.H ..Ivl .LI .... _ T . A . . . .... .IAIAAI .Ia. .r .4 I . . 3 -.4 L r, A I n I I r . ... A III. A I I- IAIIII.II.III.IIIIOII' n ,‘l. . I . rIIl‘l III In, I.I .I #1 . I. I O I . I I I Noam; . A . _ _ A W -.III._ 0 III} 111...: TIIIIIIIIIIIII 7‘ _ A A _ I A -... Mm~~w_._~. ——.._ .... ...—~— '. ELMLER‘ CORP IRKN‘ A _ . I.IIII III- IIIIIIII.IIIIIII IIIA IIIIIIIIIIIITIIIIIIIII .IIII..-I . ..I-l '4 IX’I’A IIIII IIII‘II.II.¢I.IIII.. g xufi ‘— T . l I . ‘— [L I5 J ; THE P I.II 1 “WI A v.3 ..1‘. . IIIIAIII‘I. IIII..IIIIII I a 1".) I , IIIOIII'I AIIoliulI. x \ “NA __:I.V__._ H I3 H ..IIIIIA [IIIAITII _ -.IHA III-.. . I“ i... I III I_ I ..I .II I.IILiIIIIIIf I2 I s_-‘__..‘__.A___v~_._.___- .. -v..-_.-_ .~..- — -..---” _ , I I I I r24 "WW "-""‘II"*" mxrv-"I I""’ 60 I 40 O I J)?” r vr I I I IIII --III-II .III.II!..,.,.I.II III w A -<-- - ._ w— P— “ma-.1 v.1 I I WW]: I, , II ... “.....— ‘.__.___-..._. _I~—.—_.~.- -_ I I ’nanq-v I“ . i “3...; I .1. ML hija'h‘} is“ M I I I ALA I I K ’\ {000 2:50 900 II I I I I I ”Win; loll..- ,I'I! IO I L_...__._ .— . “I -... _..__. . .. 9 t“1 I I I “* Mwwfi .4 J W “ 4* I 1 {1... K .1 I290 ,J'I M7 .40 o 0 I . r. . IKlA I 1‘ a f A _r y :3? _. 8 A H A, Ax A II. J I .«Ib’AvIoIJIBrIIM l . a! 14 II“ .,9 I.I...“ 1'“ .I w I»): _ w it :1}; A I I i L w _ 3 f1} f _ I“ II. n ‘_ Ill-...I e...’..\.!n...;!fl 7‘ «\v...§u§ ...I ..I A A _ “L 0-]! “ A MA) A _ A “kfl.;|l VII-I.I: #1 3.1.54 I h . c A I A u A . .A-f. _ I I. . _ W . v I? .1 v _ A . r,.~.l..p w .w I— f.“ .O‘Ii.o.rI-. '50 I r WAVELENGTH (MICRONS) . - h ”a 4H 14‘ in Is} ~ I vJleIl‘u'I-jv 3.. u A A J I; . p . ii A 7“ :lfiirta’ 974 . . I mi 4.49”” ‘ / A A g A I. ... 7w t~..ll-§II!17“‘LrII *‘IIEL % I I- I MEI- III :5: L: IIIIAIIII II .v .I.}: [U R15. LI; N . ‘AV!.QI¢;I.~X .../A r _ I. _ Tqul‘ :2. III! H II “at: _ .«II (I‘D.m.;.i—¥n‘.. — _ w I \r 4!: JIJOITI: A A w A I N» _ 1..., A A . __ A I!!! II _ \ ._ m . A v L _ A I. . , m . A _ A I _ w __ M m A m _ _ _ . G I I_ w ,m H _ . M _ A 4 , I- I II I- I- I . , ..TIIII- I N I ..I . ., _ _ A . n w «:3 H... A h. ._ w _ _ A A A . A 1+ _ h A _ . A u was W ‘ _ . _ u v I. A p '1 -< __._ . --....AJAW- I. ——-v--‘-0 *w— +—-¢ ......A--1_ . L AJ'V" If. ! k \JO ~ IIIIIIIIIII=.:.. I_I “ I I ‘ Mmr'flw WWW“ WM‘WMISM “I! _ . ""‘h “‘3 I A: I in: I W; _ , A A _ II IIII II ----IIEIIIII-II.I-I III! P I II IIIIII IIWI A _ . A u _ A . ... A ‘3. 4.” — m I. ~95 . I I 1C III .{ CI. 0 I I Ia I O I OrIJ 1+ I .0... ...O .H .9.» L _ . , II III I... L“ , . _ I . , _ I I . A -.A I I I I 7mm.“ ‘ 7 j in: . , II _ . ...:d f .AYIII I A, .4 - - N J . 1». PP r v if” . v fl I 4 I III... 5:334 . j 311? . I If II .1 IILIIIIIIW. II I A 1H I III In! W — ... ... c ..3. v .9!’ .W\ ...I! I 11'. ran fill}. rm b.09l31707l't}... 3" jwiLfiluqul I I.I LY. Q n . v «(.17 ~ all a I. v ’.l!| A IagfiL.a'-ID(.HJ . INFL. ] ruv I ‘1'. ' .F.$.HA7..I.1 I 300C) , 25% I i I III _ II A A! . .II .III Iw I IIIII. * _ 9. 61:0... 4.. 7.5.7}; avlivil hill? F ....IX..I{-I “...!le 3. .blmoll..fil§|.. Illll A ”W . :SILTII I x 72. 7.1.31 3 I v I ... Vii?! I HI I'll" A ---I -M I I -I- ,TA- AI _ , W . .w ...)4 I A ,. . 1... A A 1.1... W n. M II.‘ 4 II. A A ,4 k I I Eur: r #1; i! 1. III-I 5301.]: xii] w I— ..II‘ x I f 4“ h _ .... 4k»: A II _ A w ..-I _ . _ I . m. f I _ .- II V. I. m m u A I S Code?I EXPr 00 4000 - I I L_L i I \W‘AVWI‘ 'I {I .I 5 I A _ . I A_II II. I I III! I. m _ A I»: _ III _ A .J w __ O .0 O m m I 2 “Emufimw mUZ it?” {E I00 50 Ebert and Gottlieb22 have also reported differences in in- frared data between polymorphic forms of the same material. These data show that a change of the order of magnitude observed in the transition of boron triselenide from the amorphous to the crystalline form is to be expected. 51 Solubilities Boron triselenide decomposes in hot and cold water and is apparently insoluble in freshly dried carbon disulfide. Boron-Tellurium Reaction No product formed when solid boron and tellurium vapor were reacted at 10500. That only tellurium metal collected on the fritted disk, was indicated by its lack of reaction with water. These results agree with those of Moissan7 and Sabatiers, each of whom reported that this reaction did not occur 0 SUMMARY Boron triselenide was synthesized by reacting solid boron with selenium vapor at temperatures from 850° to 950°. A hydrogen sweep was used to carry the selenium vapor over the boron in a tantalum boat. The extreme moisture sensitivity of the yellow solid product made it necessary to carry out all essential work in a dry box. This moisture sensitivity which made it ex- tremely difficult to obtain accurate physical data led to the hydrolysis equation; 325e3 + 6H20 -———a——- 2H3BO3 + 3H2 + 3Se when all X—ray and infrared data on the hydrolyzed form proved identical with that for boric acid, and the resulting product was red. By working in an argon atmosphere in a dry box, it was possible to load capillaries and obtain Bragg "d values" which tended to propose that the boron triselenide lattice was that of a distorted cube. Infrared bands were also ob- tained on the boron triselenide product by making mulls and preparing the plates in the dry box. Bands were obtained on the initial product, which was shown to be amorphous, and on the heated product, which was crystalline. A shift was noted when the bands for each form were compared. The crystalline form of boron triselenide appeared to be partly covalent, having a decomposition point in vacuum of 556i50. The decomposition products appeared to be selenium 52 53 and either boron or a lower boron selenide.. Suggestions for Future Research Boron triselenide has proved to be a very interesting compound. It seems that other methods of synthesis should be tried and reactions of the resulting product studied. Perhaps reacting boric oxide with various metal selenides or reacting boron with selenium oxides would result in product formation. A measurement of vapor pressure over the solid could also be investigated. More precise information is needed on the crystal structure of this compound. Since boron and tellurium vapor did not react at 10500, it is possible that reactions between tellurium oxides and boron should be investigated. Infrared and X-ray data on a boron telluride, along with the present data on the other boron chalcogenides, would give much insight into both the chemistry of boron and of the oxygen family. 12. 13. 19. 15. 16. 17. BIBLIOGRAPHY J. J. Berzelius, Pogg, Ann. g, 113 (182%). F. Wehler and H. St. C. Deville, Ann. Chem. Phys. 5g, 90, (1858). P. Sabatier, Compt. rend. 112, 862 (1891). H. Moissan, lgig,‘ll§, 203 (1892). P. Sabatier, Ibid, 112, 1000 (1891). H. Moissan, lpig, 113, 617 (1892). H. Moissan, Ann. Chem. Phys. (7) g, 312 (1895). E. Tiede and M. Thimann, Ber. 52, 1703 (1926). P. B. Zeeman, Phys. Rev. 89, 902 (1950). F. T. Greene and J. L. Margrave, J. Am. Chem. Soc., 8;, C. D. Parkes and J. w. Mellor, Mellor's Modezn Iggrgagic Chem;§t%1, Third Edition, Longmans, Green and Co., London 19h6), page hh6. Handbook of Chemistry and Physics, 32nd, Edition, Chemical Rubber Publishing Company. R. K. McAlpine and B. S. Soule, Prescott and Johnson's Q331i§atix§ h mi a1 Analysis, D. Van Nostrand Company, Inc. 1933 , page . ' A. I. Vogel, A ngtbgok gg Macro and Semimicrg Qualita- tige Inorgagig Aga sis, Fourth Edition, Longmans, Green and Co., London 1953), page 502. H. H. Barber and T. I. Taylor, Semimicgo Qualitgtigg Analysis, Revised Edition, Harper and Brothers, Inc., New York (1953), page 338. H. H. Barber and T. I. Taylor, Ibid, page 317. w. F. Hillebrand, G. E. F. Lundell, H. A. Bright, and J. I. Hoffman, Applied Inorganic Analysis, Second Edition, John Wiley and Sons, Inc., New York (1953), page 33%. 5t 18. 19. 20. 21. 22. 55 S. Barabas and w. C. Cooper, Anal. Chem. 28, 129 (1956). I. M. Kolthoff and E. B. Sandell, Textbook 9: Quantita- tive Inor anic Anal sis Third Edition The MacMillan Company (1952), page 538. , F. A. Miller and C. H. Wilkins, Anal. Chem. 23, 1253 (1952). J. M. Hunt M. P. Wisherd, and L. C. Bonham, Anal. Chem. 22, me (1950). A. A. Ebert and H. B. Gottlieb, J. Am. Chem. Soc. 23, 2806 (1952). APPENDIX A Following, in detail, are the experimental apparatus changes involved in Series III, IV, and V. Sgries 1;; An apparatus as shown in Figure II was used for this series of tests (see page 10). As in Figure I, page 8, A, B, C, D, and E are the furnace, the 1.7 centimeter diameter Vycor tube, the crystalline boron, Pyrex flask, and sulfur, respectively. A 1h/3535 Joint was placed at the outlet end of the reaction tube. A rubber stopper with a small Pyrex tube was placed at F to allow passage of prepurified nitro- gen to the water trap. As previously, this apparatus proved ineffective even when the sulfur was heated to boiling. After one hour of boiling, only a slight haze formed in the cooled portion of the system. The ease of boiling the sulfur led to the sub- stitution of a new flask for the one used in this series of reactions. This modified apparatus was used in the next series of tests. misafl Because of the ease of boiling the sulfur and passing nitrogen gas through it, the flask as shown in Figure III, page 11, was substituted in the apparatus of Figure II. Through the use of this flask it was felt that a large quantity of sulfur vapor could be forced into the reaction chamber. Crystalline boron, C, was spread thinly over the 56 57 bottom of the Vycor reaction tube and a nitrogen flow rate of approximately ten cubic centimeters per minute was used as in previous trials. The reaction was carried out at 730°. After the reaction had proceeded for thirty minutes a large quantity of a dust-like product was swept from the furnace, but it subsided quite rapidly. No other material was noted until the second hour of reaction when a slight amount formed. These observations may result from the vari-‘ ations in fluidity of sulfur as it is heated. The quantity of nitrogen gas entering the system apparently diminished as the sulfur passed from the first liquid stage to the syrupy stage and increased as the temperature increased sufficiently to transform the syrupy stage to the second liquid stage. The decrease in nitrogen flow resulted in a poor yield of product. After five hours of reaction only a slight amount of product was formed. This apparatus was apparently inadequate because the sulfur vapor did not enter the reaction zone in a large enough volume to form the product. Some precipitated sulfur was found at the inlet end of the Vycor reaction tube, but none at the outlet end. An apparatus with a shorter path for vapor travel seemed necessary. Series 1 Figure IV, page 12, shows the re-designed apparatus used in the next series of reactions. The right hand portion of the apparatus is the same as in Figures II and III. A shorter 58 path from the sulfur to the indented Vycor reaction tube has been made. The reaction was found to proceed at a very good rate at 710° using this apparatus. In fact, considerable product was lost in the form of white fumes which escaped into the water trap. The addition of a cold trap at the outlet end of the apparatus did not stop the escape of these fumes. The large volume of these fumes indicated that a product had formed and it was concluded that the shorter distance for vapor travel had improved this yield. As a result, this feature was incorporated into all subsequent apparatus designs. APPENDIX B Calculation of Percent Selenium Weight of dry flask and product - 30.03395 grams Weight of dry flask - 22.8162% grams Weight of product - 0.2177 grams Add NaOH, H01, filter, dry, and weigh Weight of selenium and filter paper - 2.5H952 grams Weight of filter paper - 2.h3k9% grams Weight of selenium - 0.11 grams Weight of selenium and drying tube - 20.56765 grams Weight of drying tube - 0 h #00 grams Weight of selenium -. 0.0 3 grams Total selenium - 0.19820 grams PERCENT SELENIUM = 0'1 820 grams x 100 0.2177h grams = 91-03% 59 APPENDIX C Calculation of Percent Boron Weight of dry flask and product 10.8%927 grams Weight of dry flask - 10,2826h grams Weight of product - 0.0 3 grams Titration of mannitol sclution of product required 6.12 milliliters of 0.08585N NaOH 6.12 milliliters = 0.525% milliequivalents Therefore, the percent boron equals: 100 x 0.909053% x31o,8 : 8.51% Where 10.8 is the molecular weight of Boron 60 APPENDIX D Reading of X-ray film and calculation of "d values" Right Left Sum Delta 0 51n2 0 18.655 5.220 23.865 13h.25 33033' 0.305% 16.215 7.650 23.865 85.65 21°2u' 0.1331 16.100 7.760 23.860 8 .uo 200511 0.1267 15.8h5 8.020 23.865 7 .25 19033' 0.1120 15.730 8.125 23.855 76.05 19°01' 0.2061 15.335 8.5u0 23.875 67.95 16°59t 0.085 15.100 8.755 23.855 63.u5 150521 0.07% 1n.810 9.0u0 23.850 57.70 1u°261 0.0621 1h.660 .205 23.865 5h.55 13°38' 0.0556 9 1h.290 9.570 23.860 h7.20 110581 0.0h18 19.215 9.6u5 23.860 u5.70 11°26' 0.0393 1h.100 9.765 23.875 A .ns 10°52' 0.0355 13.290 10.575 23.865 2 .15 6032' 0.0129 A : 2dsin0 When./A: 1.5M18A and e = 6032' 1.5u181 2d (0.1138) 0.7709 ; (0.1138)d 6.77 = d 61 CH EMISTRX LIBRARY F.1‘l‘.0, -..-"OIII! .I‘f'lll 1‘ I! 14 1 1' . .I.! Ill-IV: