MANGANESE-DOPED BISMUTH VANADATE SOLID ELECTROLYTES .1. SYNTHESIS ANDCHARACTERIZATION OF BI2V1-XMNXO5.5-X ESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-0.25)

The solid solution series Bi2V1-xMnxO5.5-x (0.10 less than or equal to x less than or equal to 0.25) has been prepared by conventional solid -state reaction and by crystallization from the melt. After additional subsolidus annealing both procedures yielded tetragonal phases with s imilar structures and lattice constants, as determined by X-ray powder diffraction. Partial substitution of manganese on the vanadium sites stabilizes Bi2V1-xMnxO5.5-x in the high-temperature tetragonal (gamma) structure of Bi2VO5.5 for compositions in the range 0.10 less than or equal to x less than or equal to 0.25. The structures of four composi tions have been investigated by combined Rietveld refinements of X-ray and neutron powder diffraction data. Further characterization studies by transmission electron microscopy, magnetic susceptibility measurem ents and differential thermal analysis are described.