Acta Crystallographica Section E: Crystallographic Communications (Aug 2016)

Synthesis, crystal structure and charge-distribution validation of β-Na4Cu(MoO4)3 adopting the alluadite structure-type

  • Wassim Dridi,
  • Mohamed Faouzi Zid

DOI
https://doi.org/10.1107/S2056989016010367
Journal volume & issue
Vol. 72, no. 8
pp. 1103 – 1107

Abstract

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Single crystals of a new variety of tetrasodium copper(II) tris[molybdate(VI)], Na4Cu(MoO4)3, have been synthesized by solid-state reactions and characterized by single-crystal X-ray diffraction. This alluaudite structure-type is characterized by the presence of infinite layers of composition (Cu/Na)2Mo3O14 parallel to the (100) plane, which are linked by MoO4 tetrahedra, forming a three-dimensional framework containing two types of hexagonal channels in which Na+ cations reside. The Cu2+ and Na2+ cations are located at the same general site with occupancies of 0.5. All atoms are on general positions except for one Mo, two Na (site symmetry 2) and another Na (site symmetry -1) atom. One O atom is split into two separate positions with occupancies of 0.5. The title compound is isotypic with Na5Sc(MoO4)4 and Na3In2As3O12. The structure model is supported by bond-valence-sum (BVS) and charge-distribution CHARDI methods. β-Na4Cu(MoO4)3 is compared and discussed with the K4Cu(MoO4)3 and α-Na4Cu(MoO4)3 structures.

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