Tris(ethane-1,2-diamine-κ(2) N,N′)cobalt(II) cis-aqua-2κO-μ-cyanido-1:2κ(2) C:N-hepta­cyanido-1κ(7) C-bis­(ethane-1,2-diamine-2κ(2) N,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 mol­ecule. 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.