| Abstract: | The title compound, bisdiaquabis(ethylenediamine‐κ2N,N′)copper(II)] hexacyanoiron(II) tetrahydrate, Cu(C2H8N2)2(H2O)1.935]2Fe(CN)6]·4H2O, was crystallized from an aqueous reaction mixture initially containing CuSO4, K3Fe(CN)6] and ethylenediamine (en) in a 3:2:6 molar ratio. Its structure is ionic and is built up of two crystallographically different cations, viz. Cu(en)2(H2O)2]2+ and Cu(en)2(H2O)1.87]2+, there being a deficiency of aqua ligands in the latter, Fe(CN)6]4? anions and disordered solvent water molecules. All the metal atoms lie on centres of inversion. The Cu atom is octahedrally coordinated by two chelate‐bonded en molecules mean Cu—N = 2.016 (2) Å] in the equatorial plane, and by axial aqua ligands, showing very long distances due to the Jahn–Teller effect mean Cu—O = 2.611 (2) Å]. In one of the cations, significant underoccupation of the O‐atom site is observed, correlated with the appearance of a non‐coordinated water molecule. This is interpreted as the partial contribution of a hydrate isomer. The Fe(CN)6]4? anions form quite regular octahedra, with a mean Fe—C distance of 1.913 (2) Å. The dominant intermolecular interactions are cation–anion O—H?N hydrogen bonds and these interactions form layers parallel to (001). |
