Crystal structure of Ba2InTaO6 as determined by the Rietveld refinement

Rietveld profile analysis of X-ray diffraction data was carried out to determine the symmetry and crystal structures of the double perovskite Ba2InTaO6. Contrary to a recent study of Raman spectroscopy, we find no evidence that Ba2InTaO6 adopts the tetragonal space group P4/mnc of the tilt system a(0)a(0)c(+). Instead, it has cubic symmetry with the space group Fm $(3) over bar $m in the temperature range 82-723 K. In Ba2InTaO6 the ordering between In(III) and Ta(V) cations is a difficult process requiring prolonged heat treatment at high temperature. (C) 2011 Elsevier Inc. All rights reserved.