Crystal structure of bis­[(oxalato-κ(2) O (1),O (2))(1,4,8,11-tetra­aza­cyclo­tetra­decane-κ(4) N)chromium(III)] dichromate octa­hydrate from synchrotron X-ray data

The asymmetric unit of the title compound, [Cr(C(2)O(4))(C(10)H(24)N(4))](2)[Cr(2)O(7)]·8H(2)O (C(10)H(24)N(4) = 1,4,8,11-tetra­aza­cyclo­tetra­decane, cyclam; C(2)O(4) = oxalate, ox) contains one [Cr(ox)(cyclam)](+) cation, one half of a dichromate anion that lies about an inversion centre so that the bridging O atom is equally disordered over two positions, and four water mol­ecules. The terminal O atoms of the dichromate anion are also disordered over two positions with a refined occupancy ratio 0.586 (6):0.414 (6). The Cr(III) ion is coordinated by the four N atoms of the cyclam ligand and one bidentate oxalato ligand in a cis arrangement, resulting in a distorted octa­hedral geometry. The Cr—N(cyclam) bond lengths are in the range 2.069 (2)–2.086 (2) Å, while the average Cr—O(ox) bond length is 1.936 Å. The macrocyclic cyclam moiety adopts the cis-V conformation. The dichromate anion has a staggered conformation. The crystal structure is stabilized by inter­molecular hydrogen bonds involving the cyclam N—H groups and water O—H groups as donors, and the O atoms of oxalate ligand, water mol­ecules and the Cr(2)O(7) (2−) anion as acceptors, giving rise to a three-dimensional network.