Crystal structure of -di-chlorido-(1,4,8,11-tetra-aza-cyclo-tetra-decane-κ )chromium(III) bis-(form-amide-κ)(1,4,8,11-tetra-aza-cyclo-tetra-decane-κ )chromium(III) bis-[tetra-chlorido-zincate(II)].

The structure of the title compound, [CrCl(CHN)][Cr(HCONH)(CHN)][ZnCl] (CHN = 1,4,8,11-tetra-aza-cyclo-tetra-decane, cyclam; HCONH = formamide, fa), has been determined from synchrotron X-ray data. The asymmetric unit contains two independent halves of the [CrCl(cyclam)] and [Cr(fa)(cyclam)] cations, and one tetra-chlorido-zincate anion. In each complex cation, the Cr ion is coordinated by the four N atoms of the cyclam ligand in the equatorial plane and two Cl ligands or two O-bonded formamide mol-ecules in a axial arrangement, displaying a distorted octa-hedral geometry with crystallographic inversion symmetry. The Cr-N(cyclam) bond lengths are in the range 2.061 (2) to 2.074 (2) Å, while the Cr-Cl and Cr-O(fa) bond distances are 2.3194 (7) and 1.9953 (19) Å, respectively. The macrocyclic cyclam moieties adopt the centrosymmetric -III conformation with six- and five-membered chelate rings in chair and conformations The crystal structure is stabilized by inter-molecular hydrogen bonds involving the NH or CH groups of cyclam and the NH group of coordinated formamide as donors, and Cl atoms of the ZnCl anion as acceptors.