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

The title compound, (C(7)H(10)N)(2)(H(3)O)(2)[Fe(CN)(6)] or (Etpy)(2)(H(3)O)(2)[Fe(CN)(6)] (Etpy(+) is 1-ethyl­pyridinium), crystallizes in the space group Pnnm. The Fe(II) 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−).