Chromous Thiopyrophosphate, Cr₂P₂S₇

Chromous Thiopyrophosphate, Cr₂P₂S₇, is obtained as minute, black, hexagonal lamellae by the same method as the two preceding salts. It is very resistant to the action of nitric acid or aqua regia, but is decomposed by water or moist air.

Suitable mixtures for the above preparations are as follows:

	Cr	S	P
Cr3(PS3)2	1.56	1.92	0.62
Cr2P2S6	2.08	3.84	1.24
Cr2P2S7	1.04	2.24	0.62