Electronic aspect of the HSAB principle (hard and soft acids and bases)

Using the quantum mechanical SCF MO LCAO and SCF X-SW methods, we have shown the effect of the hard and soft acids and bases principle in a new aspect: Inversion of the metal halides series BX₃ and AlX₃ (X=F, Cl, Br) on going from N- to P- and from O- to S-containing bases. We have analyzed the electronic nature of the differences in the systems NH₃, PH₃ and OH₂, SH₂ responsible for the inversion of the acid series.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 22, No. 1, pp. 75–78, January–February, 1986.