Tris(ethane-1,2-diamine-κN,N')cobalt(II) cis-aqua-2κO-μ-cyanido-1:2κC:N-hepta-cyanido-1κC-bis-(ethane-1,2-diamine-2κN,N')cobalt(II)molybdenum(IV) dihydrate.

The title compound, [Co(C(2)H(8)N(2))(3)][CoMo(CN)(8)(C(2)H(8)N(2))(2)(H(2)O)]·2H(2)O, is isostructural with the Ni(II) analogue. The Mo(IV) atom is coordinated by eight cyanide ligands, one of which forms a bridge to a Co(II) atom that is itself coordinated by two bidentate ethane-1,2-diamine (en) ligands and one water mol-ecule. Another Co(II) complex, coordinated to three bidentate en ligands, acts as the counter-ion. The crystal structure contains O-H⋯N/O, N-H⋯N/O and C-H⋯N/O hydrogen bonds, which form a three-dimensional network.