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White globules of solid sulfur modification are obtained from saturated aqueous solutions. The chemical composition, morphology, and structure of the white sediment are investigated by means of X ray fluorescence analysis, scanning electron microscopy, and high resolution transmission electron microscopy. It is shown that the white sediment contains an unknown modification of globular hexagonal sulfur with glob ule sizes of 5-10 μm and interplanar distances of 0.45, 0.29, and 0.15 nm. A single absorption band at 880 cm -1 is found in the Raman scattering spectra of the saturated solutions above the sediment. It is sug gested that the white sediment consists of condensed S 2 phase.

Synthesis and study of materials based on bismuth cerates and titanates were carried out. Complex oxides Bi1.6Y0.4Ti2O7 were synthesized by the citrate route; Bi2Ce2O7 and Bi1.6Y0.4Ce2O7—by the Pechini method. The structural characteristics of materials after conventional sintering at 500–1300 °C were studied. It is demonstrated that the formation of a pure pyrochlore phase, Bi1.6Y0.4Ti2O7, occurs after high-temperature calcination. Complex oxides Bi2Ce2O7 and Bi1.6Y0.4Ce2O7 have a pyrochlore structure formed at low temperatures. Yttrium doping of bismuth cerate lowers the formation temperature of the pyrochlore phase. As a result of calcination at high temperatures, the pyrochlore phase transforms into the CeO2-like fluorite phase enriched by bismuth oxide. The influence of radiation-thermal sintering (RTS) conditions using e-beams was studied as well. In this case, dense ceramics are formed even at sufficiently low temperatures and short processing times. The transport characteristics of the obtained materials were studied. It has been shown that bismuth cerates have high oxygen conductivity. Conclusions are drawn about the oxygen diffusion mechanism for these systems. The materials studied are promising for use as oxygen-conducting layers in composite membranes.

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