Hexaaquacobalt(II) (μ2-triethyl­enetetramine­hexaacetato)di­aquadicobalt(II) tetrahydrate

The title complex, [Co(H2O)6][Co2(TTHA)(H2O)2]·4H2O (TTHAH6 = triethyl­enetetr­amine­hexa­acetic acid), consists of discrete [Co(H2O)6]2+ cations and [Co2(TTHA)(H2O)2]2− binuclear anionic units. Each Co(II) ion in the binuclear units is coordinated by one water and half a TTHA6− anion as a pentadentate ligand, giving a distorted octahedral arrangement. The [Co(H2O)6]2+ cation lies on a center of inversion in the crystal and exhibits strong hydrogen-bond interactions with four carboxyl­ate groups from the TTHA6− ligand and the water mol­ecules, leading to the formation of a three-dimensional network.