The triclinic form of dipotassium cobalt(II) bis(dihydrogendiphosphate) dihydrate

Abstract

In the title compound, K2Co(H2P2O7)2·2H2O, the octahedrally coordinated Co2+ ion lies on an inversion centre. Two bidentate dihydrogendiphosphate anions form the equatorial plane of the [CoO6] octahedron which is completed by two water molecules in axial positions. This results in isolated {Co(H2O)2[H2P2O7]2}4− entities linked into a three-dimensional network through K—O bonds and O—H...O hydrogen-bonding interactions involving the dihydrogendiphosphate anions and water molecules. The dihydrogendiphosphate anion, (H2P2O7)2−, is bent and shows an almost eclipsed conformation.