Received 8 October 2013
The title compound, Cd2V2O7, was obtained under hydrothermal conditions. Different from the known monoclinic form, the new polymorph of Cd2V2O7 has triclinic symmetry and is isotypic with Ca2V2O7. The building units of the crystal structure are two Cd2+ cations, with coordination numbers of six and seven, and two V atoms with a tetrahedral and a significantly distorted trigonal-pyramidal coordination environment, respectively. Two VO5 pyramids share an edge and each pyramid is connected to one VO4 tetrahedron via a corner atom, forming an isolated V4O148- anion. These anions are arranged in sheets parallel to (-211) and are linked through the Cd2+ cations into a three-dimensional framework structure.
For Ca2V2O7, isotypic with the title compound, see: Trunov et al. (1983). For the structure of the monoclinic polymorph of Cd2V2O7, see: Au & Calvo (1967). For the thermal stability of the monoclinic polymorph, see: Krasnenko & Rotermel (2010). For applications of vanadates, see: Jin et al. (2013); Valverde et al. (2012). For bond-valence analysis, see: Brown & Altermatt (1985).
Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: WM2776 ).
The authors thank the Unit of Support for Technical and Scientific Research (UATRS, CNRST) for the X-ray measurements.
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