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Published on: December 29, 2016
Tris[hexa-amminecobalt(III)] bis-[tri-oxalato-cobaltate(II)] chloride dodeca-hydrate
Ruijng Tian1, Yan Yan, Cailing Zhang
1Department of Materials and Chemical Engineering, Ministry of Education Key Laboratory of Advanced Materials of Tropical Island Resources, Hainan University, Haikou 570228, People’s Republic of China.
Abstract:
The title compound, [Co(III)(NH₃)₆]₃[Co(II)(C₂O₄)₃]₂Cl·12H₂O, was synthesized under hydro-thermal conditions. The asymmetric unit comprises two [Co(NH₃)₆]³⁺ cations, one located on a threefold axis and the other on a site of symmetry -3, a [Co(C₂O₄)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 NH₃ mol-ecules, forming [Co(NH₃)₆]³⁺ octa-hedra, with Co-N distances in the range 1.958 (2)-1.977 (3) Å. The title structure gives the first example of the [Co(C₂O₄)₃]⁴⁻ anion, with the distorted octa-hedral 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 mol-ecules into a three-dimensional network.
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