[Al(H2O)6][Cr(OH)6Mo6O18]•10H2O

The title compound, [Al(H2O)(6)][Cr(OH)(6)Mo6O18]center dot 10H(2)O, hexaaquaaluminium hexahydroxidooctadecaoxidomolybdochromate(III) decahydrate, crystallizes isotypically with its gallium analogue [Ga(H2O)(6)][Cr(OH)(6)Mo6O18]center dot 10H(2)O. In the structure of the title compound, both the [Al(H2O)(6)](3+) cation and the Anderson-type [Cr(OH)(6)Mo6O18](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 center dot center dot center dot O hydrogen bonds into infinite chains along [100]. These chains are further connected with the [Al(H2O)(6)](3+) cations through O-H center dot center dot center dot O hydrogen bonds into sheets parallel to (01 (1) over bar). O-H center dot center dot center dot O hydrogen bonds involving all the lattice water molecules finally link the sheets into a three-dimensional network.