Nickel Thio-orthophosphate, Ni₃(PS₄)₂

Nickel Thio-orthophosphate, Ni₃(PS₄)₂, is obtained by heating the requisite quantities of anhydrous nickel chloride and phosphorus pentasulphide in a retort:

3NiCl₂ + 2P₂S₅ = Ni₃P₂S₈ + 2PSCl₃.

The thiophosphoryl chloride distils over, and the residue is freed from nickel chloride by treatment with hydrochloric acid, washed and dried.

The salt yields brownish black crystalline plates, which ignite on heating in air, evolving sulphur dioxide.