Ab initio determination of crystal structures by X-ray powder diffraction: structure of Li29Zr9Nb3O40

Abstract

The structure of a new mixed metal oxide has been solved, ab initio, from X-ray powder diffraction data and refined by the Rietveld method. On the basis of the synthesis, structure refinement and microanalysis, the compound is assigned the composition Li₂₉Zr₉Nb₃O₄₀. It crystallises in the orthorhombic system, space group Immm, a, = 9.1769(2)Å, b, = 21.3113(5)Å, c, = 4.1664(1)Å. The structure is based on a distorted cubic-close-packed oxide lattice with 5% of the oxygen sites vacant, in an ordered manner. All the metals are distributed amongst all the available octahedral sites, again with ordering of (Zr/Nb) and Li. Li atoms cluster around the oxygen vacancy, leading to 4-, 5- and 6-coordinated Li sites.