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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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. An idealized equation for such a transformation is:

B₂S₃ + 3 (C₆H₅)₂C=O → B₂O₃ + 3 (C₆H₅)₂C=S

In practice, B₂S₃ would be used in excess.^[1]

Synthesis

Besides other methods the boron sulfide can be obtained by the reaction of iron or manganese boride with hydrogen sulfide at temperatures of 300°C.^[2]

2FeB + 4H₂S → B₂S₃ + FeS

The first synthesis was done by Jöns Jakob Berzelius in 1824 by direct reaction of amorphous boron with sulfur vapor.

2B + 3S → B₂S₃

Another synthesis was favoured by Friedrich Wöhler and Henri Etienne Sainte-Claire Deville first published in 1858, starting from boron and hydrogen sulfide.^[3][4]

2B + 3H₂S → B₂S₃ +H₂

References

1. ^ Sato, R. "Boron trisulfide" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. DOI: 10.1002/047084289.
2. ^ J. Hoffmann (1908). "Synthese von Borsulfid aus Ferro- und Manganbor". Zeitschrift für anorganische Chemie 59 (1): 127-135. doi:10.1002/zaac.19080590116.
3. ^ F. Wöhler and H. E. S.-C. Deville (1858). "Neue Beobachtungen über das Bor und einige seiner Verbindungen". Liebigs Annalen 105 (1): 67-73. doi:10.1002/jlac.18581050109.
4. ^ F. Wöhler and H. E. S.-C. Deville (1858). "Du Bore". Annales de chimie et de physique 52: 62-93.