The nature of the specific features of electrical properties and optical absorption edge in rare earth and 3d transition metal compounds

Peculiarity nature of electrical properties and optical absorption edge in rare-earth compounds and in compounds of 3d transition metals is considered on the basis of investigation results of relative placing of energy levels of electron configurations plotted in ferms of crystal ion model. These peculiarities are shown to be mainly determined by character of placing of the main levels of p6nlN, p5nlN+1, p5nlNn'l' and p6nlN-1n'l' configurations (nl = 3d, 4f; n'l' -indicates less localized, than nl, state of cation electron, while pδ, p5 - indicates filled one or anion electron shell with a hole, respectively)