A new decavanadate with a tricobalt(II) cation and 18-crown-6, tris{hexaaquacobalt(II)} decavanadate bis(18-crown-6) decahydrate

The title compound, [Co-II(H2O)(6)](3)[V10O28].(18-Crown-6)(2).10H(2)O, was obtained by mixing 18-crown-6 with K-2[Co-II( H2O)(6)](2)[V10O28].4H(2)O. The centrosymmetric [V10O28](6-) polyanion forms a three-dimensional network via O-H...O hydrogen bonds with water molecules. The V...V distances are in the range 3.068 (1) - 3.266 (1) Angstrom; the four types of V - O bond lengths are in the ranges 1.599 (3) - 1.611 (2) (Ot), 1.923 (2) - 2.030 (2) (Oc), 1.668 (2) - 2.110 (3) (Ob) and 2.062 (2) - 2.365 (2) Angstrom (Oh). The number of Co2+ cations in the structure could be controlled by the neutral, bulky 18-crown- 6 ether. All of the six O atoms in the 18-crown- 6 form hydrogen bonds with water molecules.