Direct evidence for 3d–2pπ-bonding in oxy-anions

Abstract

X-Ray fluorescence data for the L_2,3M transmission in the oxy-anions of second-row elements is analysed with a simple molecular-orbital model. The origin of a weak low-energy peak is explained. It is suggested that electrons from oxygen lone-pairs ‘back-bond’ with the central atoms 3d orbitals. The often intense high-energy satellites may then be interpreted as due to a 3d→ 2p transition. The observation of this satellite is thus direct evidence for 3d orbital participation in π-bonding.