Acta Cryst. (2007). E63, m2245-m2246  [ doi:10.1107/S1600536807033119 ]

Bis(4,4'-bipyridinium) bis(₅-hydrogen phosphate)pentakis(₂-oxido)decaoxidopentamolybdate dihydrate

W.-H. Chen, Y. Xiang, Z.-F. Chen, Q.-M. Wu and Q.-X. Zeng

Abstract: The title compound, (bipyH₂)₂[H₂Mo₅O₂₃P₂]·2H₂O or (C₁₀H₁₀N₂)₂[Mo₅O₁₅(HPO₄)₂]·2H₂O, contains the heteropolyanion [P₂Mo₅O₂₁(OH)₂]^4-, two diprotonated 4,4'-bipyridine (bipy) molecules as cations and two water molecules. The heteropolyanion is built up from five MoO₆ octahedra sharing four common edges and one common corner. The heteropolyanion has approximate noncrystallographic twofold rotation symmetry, the axis running through one Mo and one O atom. Five bridging O atoms between molybdenum centers connect the distorted MoO₆ octahedra to form a ring system, with ten Mo-O distances having an average value of 1.923 (2) Å. Six O atoms of the PO₃(OH) tetrahedra above and below the ring stabilize the polyanionic framework. The ten Mo-OP bond lengths differ markedly, between 2.219 (2) and 2.461 (2) Å. The ten short terminal Mo-O distances average 1.706 (2) Å. The P-O bond lengths range between 1.513 (2) and 1.567 (2) Å. The crystal packing exhibits a great number of N-HO and O-HO intermolecular classical hydrogen bonds, which link the cations, water molecules and polyanions to form a three-dimensional framework.

Online 31 July 2007

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