Silicon Thiochloride, SiSCl₂

Silicon Thiochloride, SiSCl₂, is formed, together with silicon disulphide and silicon tetrachloride, when the vapour of sulphur mono- chloride reacts with crystallised silicon at a red heat. The product is purified by crystallisation from carbon tetrachloride, and sublimed at 100° C. in a stream of dry air. It has also been prepared by the prolonged interaction of silicon tetrachloride vapour and hydrogen sulphide at a dull red heat, when the following changes take place:

SiCl₄ + H₂S → SiCl₃SH + HCl → SiCl₂S + HCl.

This compound crystallises from carbon disulphide in colourless prisms which melt at 74° C. (Besson) or 75° C. (Blix and Wirbelauer); the liquid boils at 92° C. under 22.5 mm. pressure (Blix and Wirbelauer). Water and moist air decompose silicon thiochloride with evolution of hydrogen chloride and sulphide and separation of silicic acid; while heat breaks it up into silicon tetrachloride and disulphide.