Crystal structure of bis­­(1-ethyl­pyridinium) dioxonium hexa­cyanidoferrate(II)

The title compound, (C7H10N)2(H3O)2[Fe(CN)6] or (Etpy)2(H3O)2[Fe(CN)6] (Etpy+ is 1-ethyl­pyridinium), crystallizes in the space group Pnnm. The FeII atom of the [Fe(CN)6]4− anion lies on a site with site symmetry ..2/m, and has an octa­hedral coordination sphere defined by six cyanido ligands. Both the Etpy+ and the oxonium cations are located on a mirror plane. In the crystal, electron-donor anions of [Fe(CN)6]4− and electron-acceptor cations of Etpy+ are each stacked parallel to the b axis, resulting in a columnar structure with segregated moieties. The crystal packing is stabilized by a three-dimensional O—H⋯N hydrogen-bonding network between the oxonium ions and the cyanide ligands of [Fe(CN)6]4−.