[Al(H2O)6][Cr(OH)6Mo6O18]·10H2O

Abstract

The title compound, [Al(H2O)6][Cr(OH)6Mo6O18]·10H2O, hexaaquaaluminium hexahydroxidooctadecaoxidomolybdochromate(III) decahydrate, crystallizes isotypically with its gallium analogue [Ga(H2O)6][Cr(OH)6Mo6O18].10H2O. In the structure of the title compound, both the [Al(H2O)6]3+ cation and the Anderson-type [Cr(OH)6Mo6O18]3− anion lie on centres of inversion. The anion is composed of seven edge-sharing octahedra, six of which are MoO6 octahedra that are arranged hexagonally around the central Cr(OH)6 octahedron. The anions are linked to each other by O—H...O hydrogen bonds into infinite chains along [100]. These chains are further connected with the [Al(H2O)6]3+ cations through O—H...O hydrogen bonds into sheets parallel to (01overline{1}). O—H...O hydrogen bonds involving all the lattice water molecules finally link the sheets into a three-dimensional network.