A neutron powder diffraction study on BaBi0.5Sb0.5O3

The crystal structure of ordered perovskite BaBi0.5Sb0.5O3 has been reinvestigated by Rietveld analysis of neutron powder diffraction data. It was found that the rhombohedral space group R3̄ describes better the structure, which can be viewed as distortions from the ideal cubic perovskite by the cooperative tilt of BiO6 and SbO6 octahedra and the systematic oxygen displacement away from Bi towards Sb. The refined Bi–O and Sb–O bond distances are 2.278 and 2.020 Å, respectively, characteristics of Bi(III) and Sb(V) ions.