Crystal structure of bis­[trans-di­chlorido­bis(propane-1,3-di­amine-κ(2) N,N′)chromium(III)] dichromate from synchrotron data

The structure of the title compound, [CrCl(2)(tn)(2)](2)[Cr(2)O(7)] (tn = propane-1,3-di­amine; C(3)H(10)N(2)), has been determined from synchrotron data. The asymmetric unit contains one Cr(III) complex cation and half a [Cr(2)O(7)](2−) anion. In the complex cation, the Cr(III) ion is coordinated by the four N atoms of two propane-1,3-di­amine (tn) ligands in the equatorial plane and by two Cl atoms in a trans configuration, displaying a distorted octa­hedral coordination sphere. The two six-membered rings in the complex cation have an anti chair–chair conformation with respect to each other. The mean Cr—N(tn) and Cr—Cl bond lengths are 2.09 (1) and 2.320 (2) Å, respectively. The slightly bent dichromate anion is disordered over two sets of sites (occupancy ratio = 0.7:0.3) and has a staggered conformation. The crystal structure is stabilized by inter­molecular hydrogen bonds involving the NH(2) groups of the tn ligands as donors and the O atoms of the [Cr(2)O(7)](2−) anion and chlorido ligands as acceptors.