Acta Cryst. (2009). E65, i45  [ doi:10.1107/S1600536809018108 ]

Nd₂(WO₄)₃

M. Weil, B. Stöger and L. Aleksandrov

Abstract: The title compound, dineodymium(III) tris[tungstate(VI)], is a member of the Eu₂(WO₄)₃ structure family and crystallizes isotypically with other rare earth tungstates and molybdates of this formula type. The structure is a derivative of the scheelite (CaWO₄) structure and can be considered as an ordered defect variant with a threefold scheelite supercell and one rare earth (RE) site unoccupied. The Nd³⁺ cations are coordinated by eight O atoms in form of a distorted bicapped trigonal prism. The two unique W cations are tetrahedrally surrounded by O atoms. One WO₄ tetrahedron has 2 symmetry and is relatively undistorted whereas the other tetrahedron differs considerably from an ideal geometry. This is caused by an additional remote O atom at a distance of 2.149 (4) Å. The resulting WO_4 + 1 polyhedra form W₂O₈ dimers through edge-sharing. Together with the WO₄ and NdO₈ units, the three-dimensional set-up is accomplished.

Online 23 May 2009

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