Equivalence of the covalent and ionic models examples

In the covalent model, the oxidation state of the metal, no, is equal to the charge left on the metal after having carried out a fictitious dissociation of the complex in which all the ligands take the two bonding electrons with them ( 1.1.2.2). For a complex whose general formula is [ML XJ, one therefore obtains no = x + q (see equations (1.2) and (1.3)). In the ionic formulation of this same complex, (see equation (1.6)), the charge on the metal is just equal to x + q, so the ionic and covalent models lead to the same oxidation state no for the metal. It follows that the same electronic configuration d is obtained by the two models, since n is equal to the number of valence electrons on the metal (m), minus its oxidation state no (equation (1.4)). 

The equivalence of the two models for the calculation of the total number of electrons in a complex (Nt) is shown by a further look at the four examples above. 

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