Acta Crystallographica Section B

Structural Science

Volume 56, Part 4 (August 2000)

research papers

Acta Cryst. (2000). B56, 565-569 [ doi:10.1107/S0108768100002615 ]

Bond-valence parameters for ammonium-anion interactions

L. García-Rodríguez, Á. Rute-Pérez, J. R. Piñero and C. González-Silgo

Abstract: Bond-valence parameters r₀ and b, relating bond valence and bond length, are calculated for interactions between the ammonium ion and anions X = O, F, Cl. Searches in the Cambridge Structural Database (CSD) and in the Inorganic Crystal Structural Database (ICSD) were performed to obtain the lengths of NH₄⁺X contacts for ammonium ion environments in different structures. The procedure, which represents an extension of previous methods, allows certain environments to be rejected and enables the calculation of r₀ and b from a reasonable range of interaction distances. Results are in very good agreement with the expected values on the basis of the assumed bond-valence model and their overall applicability to ammonium ion interactions is discussed.

Keywords: Bond-valence parameters; Ammonium; Database search.