Nd₂(WO₄)₃

Abstract

The title compound, dineodymium(III) tris[tungstate(VI)], is a member of the Eu 2 (WO 4 ) 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 (CaWO 4 ) structure and can be considered as an ordered defect variant with a threefold scheelite supercell and one rare earth ( RE ) site unoccupied. The Nd 3+ 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 WO 4 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 W 2 O 8 dimers through edge-sharing. Together with the WO 4 and NdO 8 units, the three-dimensional set-up is accomplished.