Redetermination of the cubic struvite analogue Cs[Mg(OH(2))(6)](AsO(4))

In contrast to the previous refinement from photographic data [Ferrari et al. (1955 ▶). Gazz. Chim. Ital. 84, 169–174], the present redetermination of the title compound, caesium hexa­aqua­magnesium arsenate(V), revealed the Cs atom to be on Wyckoff position 4d instead of Wyckoff position 4b of space group F [Image: see text]3m. The structure can be derived from the halite structure. The centres of the complex [Mg(OH(2))(6)] octa­hedra and the AsO(4) tetra­hedra (both with [Image: see text]3m symmetry) are on the respective Na and Cl positions. The building units are connected to each other by O—H⋯O hydrogen bonds. The Cs(+) cations ([Image: see text]3m symmetry) are located in the voids of this arrangement and exhibit a regular cubocta­hedral 12-coordination to the O atoms of the water mol­ecules. The O atom bonded to As has 2mm site symmetry (Wyckoff position 24f) and the water-mol­ecule O atom has m site symmetry (Wyckoff position 48h).