Bis[tris-(ethyl-enediamine-κN,N')cobalt(III)] octa-kis-μ-(3)-oxido-hexa-deca-μ(2)-oxido-tetra-deca-oxido-μ(12)-tetra-oxo-silicato-octa-molybdenum(VI)hexa-vanadium(IV,V) hexa-hydrate.

The title compound, [Co(C(2)H(8)N(2))(3)](2)[SiMo(8)V(4)O(40)(VO)(2)]·6H(2)O, was prepared under hydro-thermal conditions. The asymmetric unit consists of a transition metal complex [Co(en)(3)](3+) cation (en is ethyl-enediamine), one half of an [SiMo(8)V(4)O(40)(VO)(2)](6-) heteropolyanion, two solvent water mol-ecules in general positions and two half-mol-ecules of water located on a mirror plane. In the complex cation, the Co(3+) ion is in a distorted octa-hedral coordination environment formed by six N atoms of the three chelating en ligands. One of the en ligands exhibits disorder of its aliphatic chain over two sets of sites of equal occupancy. The [SiMo(8)V(4)O(40)(VO)(2)](6-) heteropolyanion is a four-electron reduced bivanadyl-capped α-Keggin-type molybdenum-vanadium-oxide cluster. In the crystal, it is located on a mirror plane, which results in disorder of the central tetra-hedral SiO(4) group: the O atoms of this group occupy two sets of sites related by a mirror plane. Furthermore, all of the eight μ(2)-oxide groups are also disordered over two sets of sites with equal occupancy. There are extensive inter-molecular N-H⋯O hydrogen bonds between the complex cations and inorganic polyoxidoanions, leading to a three-dimensional supra-molecular network.