Crystal structure of hexakis(urea-κO)chromium(III) dichromate bromide monohydrate from synchrotron X-ray data

Abstract

The title bromide salt, [Cr{CO(NH2)2}6](Cr2O7)Br·H2O, is isotypic to the corresponding chloride salt. Within the complex cation, the CrIII atom is coordinated by six O atoms of six urea ligands, displaying a slightly distorted octahedral coordination environment. The Cr - O bond lengths involving the urea ligands are in the range 1.9534 (13)-1.9776 (12) Å. The Cr2O72- anion has a nearly staggered conformation, with a bridging angle of 130.26 (10)°. The individual components are arranged in rows extending parallel to [100]. The Br- anion links the complex cation, as well as the solvent water molecule, through N - H⋯Br and O - H⋯Br hydrogen-bonding interactions. The supramolecular architecture also includes N - H⋯O and O - H⋯O hydrogen bonding between urea N - H and water O - H donor groups and the O atoms of the Cr2O72- anion as acceptor atoms, leading to a three-dimensional network structure.