A theoretical study of the bonding in NO, (NO)2, (NO)2− and (NO)22− using a topological analysis of the electron localization function

Abstract

The topological analysis of the ELF function calculated at the DFT level for (NO)₂, (NO)₂⁻ and (NO)₂²⁻ reveals a regular variation in the NN bonding. In the neutral species, a very weak attraction results form the fluctuation of a small electron population associated with the N lone pairs. A similar but even weaker attraction is found between the O atoms, thus favouring the cis geometry. The same trends are found in the cis anion, although in the more stable trans isomer a NN bonding basin appears. The latter bonding basin is more pronounced in the dianions. The molecular orbital localization function (MOLF) method which is briefly described, is proposed for gaining information on the σ/π separation.