Cerous orthophosphate, CePO₄

The dihydrate, CePO₄.2H₂O, is obtained by double decomposition between a cerous salt and phosphoric acid or an alkali phosphate. When dried it forms a white, amorphous powder, from which orthorhombic crystals of density 5.09, closely resembling the mineral monazite, may be obtained by heating to redness with excess of fused cerous chloride. The phosphate dissolves in the molten chloride and crystallises out on cooling.

The double phosphates, K₃PO₄.2CePO₄, and Na₃PO₄.2CePO₄, have been obtained by Ouvrard.

Cerous pyrophosphate, Ce₄(P₂O₇)₃.12H₂O, cerous hydrogen pyrophosphate, CeHP₂O₇, and cerous sodium pyrophosphate, CeNaP₂O₇, have been described, and likewise cerous metaphosphate, Ce(PO₃)₃. Cerous pyrophosphate is readily soluble in dilute mineral acids.