MO MODEL OF ELECTRON DELOCALIZATION IN MIXED-VALENCE BIOCTAHEDRAL CLUSTERS

A simple extended Huckel type molecular orbital model is proposed for mixed-valence bioctahedral clusters. The model allows the study of the delocalisation of the excess electron in these systems as a function of the arrangement of octahedral units, metal-metal distances and elec tronic configurations. Fe(II)-Fe(III) clusters with oxygen ligands are considered as examples. It is shown that the model provides informati on about the electronic structure of mixed-valence clusters which cann ot be obtained from phenomenological vibronic theories.