Cobalt phosphate is the inorganic compound with the formula Co<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>. It is a violet solid that is insoluble in water.
According to X-ray crystallography, the anhydrous Co<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub> consists of discrete phosphate () anions that link centres. The cobalt ions occupy both octahedral (six-coordinate) and pentacoordinate sites in a 1:2 ratio.
The tetrahydrate Co<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>â¢4H<sub>2</sub>O precipitates as a solid upon mixing aqueous solutions of cobalt(II) and phosphate salts. Upon heating, the tetrahydrate converts to the anhydrous material.
Thin films of this material are water oxidation catalysts.
It is also a commercial inorganic pigment known as cobalt violet (PV14).