Phase equilibria in the system CePO4K3PO4K4P2O7

The phase diagram with liquids isotherms and isothermal section at room temperature of the system CePO4K3PO4K4P2O7 has been determined by thermal analysis, K4P2O7 powder X-ray diffraction and IR spectroscopy. The system contains two double phosphates: K3Ce(PO4)2 and K4Ce2P4O15. The first one melts incongruently at 1500 °C. The other exists only in solid state (below 880 °C). Two systems: CePO4K4P2O7 and K3Ce(PO4)2K4P2O7, which are binary only in the subsolidus region, have been found.