Received 1 October 2013
The title compound, sodium cadmium orthoarsenate, adopts the olivine [Mg2(SiO4)] structure type in space group Pnma, with Na (site symmetry -1) and Cd (.m.) replacing the two Mg positions, and the AsO4 tetrahedron (.m.) the SiO4 tetrahedron. The crystal structure is made up of a nearly hexagonal closed-packed arrangement of O atoms stacked along . The Na and Cd atoms occupy one half of the octahedral voids in alternate layers stacked along , and one eighth of the tetrahedral voids are occupied by As atoms.
For a review of the crystal chemistry of olivines, see: Brown (1982). For the isotypic phosphate analogue, see: Ivanov et al. (1974); Hata et al. (1979). For other phases in the system Na-Cd-P-O, see: Murashova & Chudinova (1997); Bennazha et al. (2000); Ben Amara et al. (1979). For standardization of structure data, see: Gelato & Parthé (1987).
Data collection: SMART (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ATOMS for Windows (Dowty, 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: PJ2006 ).
The X-ray centre of the Vienna University of Technology is acknowledged for financial support and for providing access to the single-crystal diffractometer.
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