Syntheses of various rare earth phosphates from some rare earth compounds

Each rare earth compound (rare earth element; R=La, Ce, and Nd, anion; oxide, carbonate, chloride, nitrate, sulfate, oxalate, and fluoride) was mixed with (NH4)2HPO4 or H3PO4 in P/R=1, 3, and 5, and heated in air. The resulting salts were analyzed by TG-DTA, XRD and FT-IR. CePO4·nH2O was not formed in the system of CeO2–H3PO4. However, this phosphate was synthesized in the systems of Ce(NO3)3·6H2O–(NH4)2HPO4, Ce2(CO3)3·8H2O–, CeCl3·7H2O–, and Ce(NO3)3·6H2O–H3PO4. The crystallinity of CePO4·nH2O was high in the systems of CeCl3·7H2O–, and Ce(NO3)3·6H2O–H3PO4. In P/Ce=1, formation of CeO2 was observed in the systems of Ce2(CO3)3·8H2O–, CeCl3·7H2O–, and Ce2(C2O4)3·9H2O–(NH4)2HPO4.