Cobalt(II) phosphate


Cobalt phosphate is the inorganic compound with the formula Co32. It is a commercial inorganic pigment known as cobalt violet. Thin films of this material are water oxidation catalysts.

Preparation and structure

The tetrahydrate Co32•4H2O precipitates as a solid upon mixing aqueous solutions of cobalt(II) and phosphate salts. Upon heating, the tetrahydrate converts to the anhydrous material. According to X-ray crystallography, the anhydrous Co32 consists of discrete phosphate anions that link centres. The cobalt ions occupy both octahedral and pentacoordinate sites in a 1:2 ratio.