Octakis(dimethyl sulfoxide-kO)-cerium(III) mu(6)-oxido-dodeca-mu(2)-oxidohexaoxidohexamolybdate(VI) dimethyl sulfoxide tetrasolvate

The title complex, [Ce(C2H6OS)(8)](2)[Mo6O19](3).4C(2)H(6)OS, was obtained as a byproduct of the reaction of [(C4H9)(4)N](2)[Mo6O19] with Ce(NO3)(3).6H(2)O and phthalic acid in dimethylsulfoxide solution. The asymmetric unit consists of a complex [Ce(C2H6OS)(8)](3+) cation, one and a half of the Lindqvist-type [Mo6O19](2-) polyanions and two dimethylsulfoxide solvent molecules; the half polyanion lies on an inversion center. The Ce3+ ion is coordinated by eight dimethylsulfoxide ligands through the O atoms in the form of a distorted square antiprism. The Ce-O bond lengths range from 2.429 (6) to 2.550 (5) angstrom. The cohesion of the structure is ensured by S...O [3.115 (6), 3.242 (10) and 3.12 (3) angstrom], O...O [3.037 (10) angstrom] and C-H . . . O interactions between cations and anions. The S and C atoms of a dmso ligand are disordered over three sites in a 0.45:0.30:0.25 ratio. The dimethylsulfoxide solvent molecules are highly disordered and could not be modelled successfully; their contribution was therefore removed from the refinement using the SQUEEZE routine in PLATON [Spek (2009). Acta Cryst. D65, 148-155]. Potential solvent-accessible voids of 500.0 angstrom(3) occur in the crystal structure.