Triammonium hexahydroxidooctadeca-oxidohexamolybdogallate(III) hepta-hydrate

Abstract

The title compound, (NH4)3[GaMo6(OH)6O18]·7H2O, contains two centrosymmetric GaMo6 B-type Anderson cluster units consisting of central GaO6 octa-hedra surrounded by a hexa-gonal assembly of MoO6 edge-sharing octa-hedra. Like other B-type Anderson clusters, where the central Mo atom is substituted with a di- or trivalent metal ion, the central six μ3-oxido bridges are protonated. The average Ga - O bond length is 1.97 (1) Å, whereas the average Mo - O distances are 2.29 (2), 1.94 (1) and 1.709 (5) Å, respectively, for Mo - (μ3-OH), Mo - (μ2-O) and Mo=O bonds. In the crystal structure, the Ga(μ3-OH)6Mo6O18 3- polyanionic clusters are surrounded by NH4 + cations and solvent water mol-ecules, forming an extended network of hydrogen bonds. © 2008 International Union of Crystallography.