Synthesis and Investigation of Na1 –xR0.33xTiO2(PO4)3 (R = Y or La) Phosphates

Phosphates Na 1 – x R 0.33 x Ti 2 (PO 4 ) 3 (R = Y or La; 0 ≤ х ≤ 1) were synthesized by the Pechini process and characterized by X-ray diffraction, electron microscopy with microprobe analysis, and IR spectroscopy. The systems exhibit isodimorphism to form a series of solid solutions belonging to the NaZr 2 (PO 4 ) 3 (NZP) structural type and crystallizing in space group R c or R The Rietveld structural studies confirmed the isomorphic miscibility of sodium and the rare-earth element in the interstices of the NZP structure. The unit cell parameter с in the phosphates studied tends to increase, and the parameter а tends to decrease, in response to rising temperature, which trends are typical of NZP phosphates.