Tris[hexa­amminecobalt(III)] bis­[tri­oxalato­cobaltate(II)] chloride dodeca­hydrate

The title compound, [Co(III)(NH(3))(6)](3)[Co(II)(C(2)O(4))(3)](2)Cl·12H(2)O, was synthesized under hydro­thermal conditions. The asymmetric unit comprises two [Co(NH(3))(6)](3+) cations, one located on a threefold axis and the other on a site of symmetry -3, a [Co(C(2)O(4))(3)](4+) anion, located on a threefold axis, one sixth of a chloride anion [disordered over two sites, one threefold (site occupancy = 0.5) and the other -3 (site occupancy (0.25)] and two water molecules. Both Co(III) centers are six-coordinated by NH(3) mol­ecules, forming [Co(NH(3))(6)](3+) octa­hedra, with Co—N distances in the range 1.958 (2)–1.977 (3) Å. The title structure gives the first example of the [Co(C(2)O(4))(3)](4−) anion, with the distorted octa­hedral environment of Co(II) center formed by six O atoms from three oxalate residues. The Co—O bond lengths are 2.0817 (18) to 2.0979 (18) Å. Multiple N—H⋯O, N—H⋯Cl and O—H⋯O hydrogen bonds link the cations, anions and water mol­ecules into a three-dimensional network.