Spectroscopic characterization of cobalt doped bismuth tantalate pyrochlore

The new pyrochlore with the composition Bi1·6Co0·8Ta1·6O7±Δ (sp. gr. Fd-3m:2, 10.5526 (2) Å, Z = 8 (No. 227)) was obtained by the method of solid-phase synthesis. The sample is characterized by a dense microstructure with a small number of pores formed by partially fused grains. The electronic states of the atoms were studied by the near edge X-ray absorption fine structure and X-ray photoelectron spectroscopy. According to spectroscopy data, it was found that bismuth atoms have an effective charge of +3, cobalt atoms +2 and tantalum ions +(5-δ). [Display omitted] •Co-doped bismuth tantalate pyrochlore were synthesized by the solid-phase reaction method.•The sample may contain up to 7 mol. % BiTaO4.•The fraction of Сo (II) ions occupying the positions of bismuth (III) was estimated.•It was found that Bi have an effective charge of +3, cobalt ions +2 and tantalum ions +(5-δ).