Crystal structure of the double magnesium zirconium orthophosphate at temperatures of 298 and 1023 K

Double magnesium zirconium orthophosphate Mg 0.5 Zr 2 (PO 4 ) 3 is synthesized by the sol-gel method. The compound prepared is characterized using electron probe microanalysis and X-ray diffraction. The crystal structure of the orthophosphate is refined by the Rietveld method in space group P 2 1 / n (Z = 4) at temperatures of 298 K [ a = 12.4218(2) Å, b = 8.9025(2) Å, c = 8.8218(2) Å, β = 90.466(1)°] and 1023 K [ a = 12.4273(5) Å, b = 8.9453(4) Å, c = 8.8405(4) Å, β = 90.320(3)°]. It is demonstrated that an increase in the temperature leads to an anisotropic expansion of the unit cell of the phosphate structure, but the structural type remains unchanged.