Boron sulfide
Boron sulfide is the chemical compound with the formula B2S3. This polymeric material that has been of interest as a component of "high-tech" glasses and as a reagent for preparing organosulfur compounds. Like the sulfides of silicon and phosphorus, B2S3 reacts with water, including atmospheric moisture to release H2S. Thus, samples must be handled under anhydrous conditions.
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| Names | |
|---|---|
| IUPAC name
 Boron sulfide  | |
| Other names
 Boron sesquisulfide, Diboron trisulfide  | |
| Identifiers | |
3D model (JSmol)  | 
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| ECHA InfoCard | 100.031.355 | 
| EC Number | 
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PubChem CID  | 
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CompTox Dashboard (EPA)  | 
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| Properties | |
| B2S3 | |
| Molar mass | 117.80 g/mol | 
| Appearance | colorless crystals | 
| Density | 1.55 g/cm3, solid | 
| Melting point | 563 °C (1,045 °F; 836 K) | 
| Boiling point | decomposes at high T | 
| decomposes | |
| Solubility | soluble in ammonia | 
| Structure | |
| monoclinic, mP40, SpaceGroup = P21/c, No. 14 | |
| B: planar, sp2 | |
| Thermochemistry | |
Heat capacity (C)  | 
111.7 J/mol K | 
Std molar entropy (S  | 
327 J/mol K | 
Std enthalpy of formation (ΔfH⦵298)  | 
-240.6 kJ/mol | 
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards  | 
source of H2S | 
| Related compounds | |
Related compounds  | 
BCl3 Lawesson's reagent  | 
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). 
Infobox references  | |
Like the boron oxides, B2S3 readily forms glasses when blended with other sulfides such as P4S10. Such glasses absorb lower frequencies of Infra-red energy relative to conventional borosilicate glasses.
B2S3 converts ketones into the corresponding thiones. For example, the conversion of benzophenone to its thione proceeds as follows:
- B
2S
3 + 3 (C
6H
5)
2C=O → B
2O
3 + 3 (C
6H
5)
2C=S 
In practice, B2S3 would be used in excess.[1]
Synthesis
    
Among other methods Diboron Trisulfide can be obtained by the reaction of iron or manganese boride with hydrogen sulfide at temperatures of 300 °C.[2]
- 2 FeB + 4 H2S → B2S3 + FeS + 4 H2
 
The first synthesis was done by Jöns Jakob Berzelius in 1824 by direct reaction of amorphous boron with sulfur vapor.[3]
- 2 B + 3 S → B2S3
 
Another synthesis was favoured by Friedrich Wöhler and Henri Etienne Sainte-Claire Deville first published in 1858, starting from boron and hydrogen sulfide.[4][5]
- 2 B + 3 H2S → B2S3 + 3 H2
 
Structure
    
The boron atoms in B2S3 are trigonal planar, and are arranged in B3S3 and B2S2 rings with bridging S atoms forming a layer structure with an interlayer distance of 355 pm. This is different from boron trioxide which has a three dimensional structure.[6]
The molecular, monomeric, form of B2S3 has a planar V shape with the central B-S-B angle of approximately 120°.[6]
References
    
- Sato, R. (2004). "Boron Trisulfide". In L. Paquette (ed.). Encyclopedia of Reagents for Organic Synthesis. New York: J. Wiley & Sons. doi:10.1002/047084289X.rb255. ISBN 0471936235.
 - Hoffmann, J. (1908). "Synthese von Borsulfid aus Ferro- und Manganbor". Zeitschrift für anorganische Chemie. 59 (1): 127–135. doi:10.1002/zaac.19080590116.
 -  Berzelius, J. (1824). "Undersökning af flusspatssyran och dess märkvärdigaste föreningar" [Investigation of hydrofluoric acid and of its most noteworthy compounds]. Kongliga Vetenskaps-Academiens Handlingar [Proceedings of the Royal Science Academy]. 12: 46–98.
Reprinted in German as:
Berzelius, J. J. (1824). "Untersuchungen über die Flußspathsäure und deren merkwürdigsten Verbindungen". Annalen der Physik und Chemie. 78 (10): 113–150. Bibcode:1824AnP....78..113B. doi:10.1002/andp.18240781002. see especially pages 145–147. - Wöhler, F.; Deville, H. E. S.-C. (1858). "Neue Beobachtungen über das Bor und einige seiner Verbindungen" [New observations concerning boron and some of its compounds]. Liebigs Annalen der Chemie und Pharmacie. 105 (1): 67–73. doi:10.1002/jlac.18581050109.
 - Wöhler, F.; Deville, H. E. S.-C. (1858). "Du Bore". Annales de Chimie et de Physique. 52: 62–93.
 - Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
 
