HYDROTHERMAL SYNTHESIS AND CHARACTERIZATION OF K2CE(PO4)(2)CENTER-DOT-H2O

A new compound in the system K2O-CeO2-P2O5-H2O (K2Ce(PO4)(2) . H2O) ha s been hydrothermally synthesized and characterized by X-ray powder di ffraction, differential thermal analysis, thermogravimetric analysis, composition analysis, IR, Raman and impedance spectra. The product cry stallized as an orthorhombic phase with a = 12.79(3) Angstrom, b = 14. 01(5) Angstrom, c = 15.94(3) Angstrom and v = 2854 Angstrom(3). The co mpound is a proton conductor at temperatures below 180 degrees C, an i nsulator between 180 degrees C and 320 degrees C, and a potassium-ion conductor above 340 degrees C. The proton conductivities of the compou nd were 1.70 x 10(-8) S cm(-1) at 40 degrees C and 1.95 x 10(-7) S cm( -1) at 160 degrees C, and the K-ion conductivity 1.62 x 10(-9) S cm(-1 ) at 340 degrees C.