The sulphydrate or hydrosulphide, Ca(SH)2, is obtained as colourless, prismatic crystals of the composition Ca(SH) 2.6H 2 O, by passing sulphuretted hydrogen into milk of lime.
An ice-cold solution of this substance kept at o C. and having sulphuretted hydrogen continually passed through it gives the hydrosulphide.
The hydrosulphide, KHS, was obtained by Gay-Lussac on heating the metal in sulphuretted hydrogen, and by Berzelius on acting with sulphuretted hydrogen on potassium carbonate at a dull red heat.
By dissolving it in a hydrosulphide a sulphotungstate is produced; these salts can also be obtained by passing sulphuretted hydrogen into a solution of a tungstate.
It is a white powder which is readily decomposed by water with the formation of the hydroxide and hydrosulphide.