This paper is devoted to the setting up of correlations between the ionocovalent parameter (ICP) and a parameter specific of the metal-oxygen bond, deduced from different spectroscopic methods (ligand field, infrared. X-ray emission and absorption and photoemission spectroscopies).

The analysis of the infrared and ligand field spectra of AB₂O₄ spinels is discussed in term of cation distribution and ionicity of these compounds. The magnetic structure`s effect is preponderant on optical spectra analysis for the 3d⁵ and 3d⁸ configuration. The ligand field spectroscopy indicates unambiguously that the fundamental states of cobalt(II), nickel(II) and copper(II) in spinels are respectively 3d⁷, 3d⁸ and 3d⁹ ; this interpretation differs from the configuration interaction model.

The analysis of the X-ray Kβ emission, M2p XPS spectra may be clearly interpreted by a charge-transfer effect during the photoionization of one of the core electrons. The effect of the electronic structure on the Kβ₅ chemical shifts of the cation in TM oxides has been established: the ΔKβ₅ - ICP diagram is correlated with the Zaanen, Sawatzky, Alien classification. A model for interpretation of X-ray absorption near-edge structure (XANES) on the basis of the multiple scattering phenomenon is presented.