Crystal structure and conductivity of bismuth-containing complex oxides

Abstract

In the paper, a comprehensive systematic study of different classes of bismuth containing oxide compounds was carried out. The relationship between composition, temperature and concentration regions of existence of stable, specific structure and properties of solid solutions on the basis of vanadates, molybdates, niobates and bismuth was found. The general regularities of synthesis of solid solutions with different variants of solid-phase and soluble methods were determined. On this basis, the optimal conditions for obtaining single-phase materials were formulated. For the first time the temperature and concentration boundaries of the regions of homogeneity and areas of stable existence of polymorphic modifications of solid solutions were defined and/or refined. The structural parameters of the synthesized phases were determined. By the method of electrochemical impedance spectroscopy the nature and features of impedance spectra, the temperature and concentration dependences of electrical conductivity of ceramic materials based on bismuth containing complex oxides were identified.

Influence of the composition of the BiPO4-BiVO4 system on the phase formation, morphology, and properties of nanocrystalline composites obtained under hydrothermal conditions

“…Bismuth vanadate of the monoclinic modification can be obtained by several methods, that differ from each other in sets of precursors, synthesis conditions, and the complexity of its implementation. The phase formation for systems containing bismuth and vanadium oxides always proceeds in several sequential-parallel stages with the formation of intermediate products [13]. Bismuth vanadate with the clinobiswanite structure can be obtained by flame pyrolysis [14], a high-temperature heat treatment [15], solution combustion [16,17], soft chemistry methods [18,19], including solvothermal [5] and hydrothermal methods [20][21][22][23].…”