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. |