Crystal Structure of Cs2Zn(NO2)4: Influence of Steric Crowding on Nitrite Coordination

The crystal structure of Cs2[Zn(NO2)4] has been determined by X-ray diffraction. Each nitrite ion in the Zn(NO 2)4 2- group forms one short [2.080(3) Å] and one long [2.516(3) A] Zn-O bond, the metal-ligand interaction being intermediate between symmetrical chelation and syn-unidentate nitrite coordination. It seems likely that this unsymmetrical geometry is adopted in order to minimize ligand-ligand repulsions, though density functional theory calculations suggest a very shallow potential energy curve for the complex. © CSIRO 2005.