Acta Cryst. (2008). E64, i8-i9  [ doi:10.1107/S1600536807068067 ]

Triammonium hexahydroxidooctadecaoxidohexamolybdogallate(III) heptahydrate

Z. L. Mensinger, L. N. Zakharov and D. W. Johnson

Abstract: The title compound, (NH₄)₃[GaMo₆(OH)₆O₁₈]·7H₂O, contains two centrosymmetric GaMo₆ B-type Anderson cluster units consisting of central GaO₆ octahedra surrounded by a hexagonal assembly of MoO₆ edge-sharing octahedra. Like other B-type Anderson clusters, where the central Mo atom is substituted with a di- or trivalent metal ion, the central six ₃-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-(₃-OH), Mo-(₂-O) and Mo=O bonds. In the crystal structure, the Ga(₃-OH)₆Mo₆O₁₈^3- polyanionic clusters are surrounded by NH₄⁺ cations and solvent water molecules, forming an extended network of hydrogen bonds.

Online 9 January 2008

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