Cupric orthophosphate, Cu₃(PO₄)₂,3H₂O

The Cupric orthophosphate, Cu₃(PO₄)₂,3H₂O, is prepared by the interaction of disodium hydrogen phosphate and excess of cupric sulphate, or by heating an aqueous solution of ortho-phosphoric acid with cupric carbonate at 70° C. It is a blue, crystalline powder, almost insoluble in water.

The basic orthophosphate, Cu₃(PO₄)₂,Cu(OH)₂, occurs as libethenite in the form of dark-green crystals, produced artificially by heating the orthophosphate with water. In combination with two molecules of water it also occurs as tagilite.