Crystal structure of bis­­[cis-(1,4,8,11-tetra­aza­cyclo­tetra­deca­ne-κ4N)bis­(thio­cyanato-κN)chrom­ium(III)] dichromate monohydrate from synchrotron X-ray diffraction data

The structure of the complex salt, cis-[Cr(NCS)2(cyclam)]2[Cr2O7]·H2O (cyclam = 1,4,8,11-tetra­aza­cyclo­tetra­decane, C10H24N4), has been determined from synchrotron data. The asymmetric unit comprises of one [Cr(NCS)2(cyclam)]+ cation, one half of a Cr2O72− anion (completed by inversion symmetry) and one half of a water mol­ecule (completed by twofold rotation symmetry). The CrIII ion is coordinated by the four cyclam N atoms and by two N atoms of cis-arranged thio­cyanate anions, displaying a distorted octa­hedral coordination sphere. The Cr—N(cyclam) bond lengths are in the range 2.080 (2) to 2.097 (2) Å while the average Cr—N(NCS) bond length is 1.985 (4) Å. The macrocyclic cyclam moiety adopts the cis-V conformation. The bridging O atom of the dichromate anion is disordered around an inversion centre, leading to a bending of the Cr—O—Cr bridging angle [157.7 (3)°]; the 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 donor groups, and the O atoms of the Cr2O72− anion and water mol­ecules as acceptor groups, giving rise to a three-dimensional network.