Platinum Monosulphide, PtS

Platinous Sulphide, Platinum Monosulphide, PtS, was obtained by Davy by ignition of platinum sponge and sulphur in a closed tube. The product was a black, refractory mass.

Roessler obtained the sulphide by heating finely divided platinum with sulphur under a layer of borax. On extracting with hot water a dark, heavy powder remains.

Other methods consist in heating to white heat a mixture of platinum and pyrites under borax, a crystalline product being thereby obtained; by heating in a closed crucible a mixture of ammonium chlor-platinate and sulphur; and, finally, by the ignition of the oxvsulphide, PtOS.Aq. The product is a greyish black, insoluble substance, not attacked by acids or alkalies, and almost insoluble in aqua regia. When heated in a current of hydrogen it is readily reduced to the metal.

At high temperatures the sulphide apparently dissociates, leaving a residue of metallic platinum.

When hydrogen sulphide is passed into an aqueous solution of an alkali chlor-platinite, a black precipitate of the monosulphide is obtained.