Crystal structure of ammonium bis(pyridine-2,6-dicarboxylato-κ3O,N,O′)chromate(III) from synchrotron data

Abstract

The structure of the title compound, (NH4)[Cr(pydc)2] (pydc is pyridine-2,6-dicarboxylate, C7H3NO4), has been determined from synchrotron data. The CrIIIion and the N atom of the ammonium cation are located on a crystallographic fourfold rotoinversion axis (-4). The CrIIIcation is coordinated by four O atoms and the two N atoms of two meridional pydc ligands, displaying a distorted octahedral geometry. The Cr—N and Cr—O bond lengths are 1.9727 (15) and 1.9889 (9) Å, respectively. The crystal structure is stabilized by intermolecular hydrogen bonds involving the N–H groups of the ammonium cation and pyridine C–H groups as donors and the non-coordinating carbonyl O atoms as acceptors.