Phase formation, structure and ion conductivity of silver antimonate-molibdats

Silver antimonate-based compounds, formed at partial substitution of ions of quinquevalent antimony with ions of hexavalent molybdenum, have been synthesized using the method of solid-phase reaction. Specificities of phase formation processes of mixtures with various mole ratios of the initial components of a system containing silver nitrate and oxides of trivalent antimony and hexavalent molybdenum have been studied in a wide temperature range from $300$ to $1023$ K. Using the thermogravimetric analysis data, optimal temperatures for synthesis of powders have been determined. Using the method of qualitative X-ray phase analysis together with the method of high-temperature X-ray diffraction, compositions of reaction products of solid-phase interaction at open air heating have been determined. For the temperature of $1023$ K, a homogenous area of formation of a solid solution of silver antimonat-molibdates with the structure of a defective pyrochlore-type within $0,0 \leqslant x\leqslant 2,0$ concentration interval has been determined. In the frameworks of $Fd$-$3m$ spatial group, a full-profile analysis (the Rietveld method) has been carried out to specify the crystal structure (coordinates of population of ions by crystallographic positions, elementary cell parameters), and interrelation in compositions of the obtained pyrochlore phases with their structural disorder and ion-conducting properties has been determined. Ceramic properties (relative density and average size of particles) of the samples sintered at the temperature of $1373$ K have been studied.