Structural and spectroscopic studies of Ba2Y1−δUO6+x

• Structure of Ba2Y0.879UO6+x refined.
• U L-edge XANES demonstrates the U is hexavalent.
• Rare example of a perovskite containing vacancies at the octahedral B-site.
• Y vacancies result in a distortion of the BO6 octahedra.

A combination of S-XRD and NPD demonstrate the structure of Ba2Y0.879UO6+x to be monoclinic in space group I2/m. That the U is hexavalent is evident from the U L2-edge XANES measurements. This appears to be a rare example of a double perovskite containing vacancies at the octahedral B-sites and interstitial oxygen defects, which combine to stabilise hexavalent U and appears to be a consequence of the preparation of the sample in air. The Y vacancies, coupled with anion disorder, results in a distortion of the BO6 octahedra.

The structure of Ba2Y0.879UO6+x is shown to be a rare example of a double perovskite containing vacancies at the octahedral B-sites and interstitial oxygen defects.Figure optionsDownload as PowerPoint slide