High pressure synthesis and structural characterization of the deficient perovskite Ba0.88NbO2.3

The title compound has been prepared from BaO, NbO2 and Nb mixtures, at 1200 °C under an hydrostatic pressure of 12 kbar. It is cubic,a = 4.3239(4)A˚, and the Rietveld analysis of the X-ray diffraction profile shows a strong deficiency in both Ba and oxygen positions. Unlike metallic BaNbO3, this defect perovskite shows insulating behavior, the oxygen vacancies hindering the electronic delocalization along the structure.