NaMg4(AsO4)3

The title compound, sodium tetramagnesium tris(arsenate), was prepared by solid-state reaction at 1243 K. The structure is built up from edge-sharing MgO6 octahedra associated with the AsO4 arsenate groups. The three-dimensional network encloses cavities in which Na+ cations are located. This compound exhibits the NaMg4(VO4)(3) structure. The Na and one of the As atoms are on positions of (4) over bar symmetry and the remaining cations all lie on twofold axes.