A molecular orbital study of the hydration of ions. The role of nonadditive effects in the hydration shells around Mg2+ and Ca2+

Abstract

The role of divalent cations in biology, in particular Ca2+ and Mg2+, has led to many studies of the coordination of these ions. The existence of empirical rules serves to characterize these properties, however, a detailed quantum mechanical analysis of the fundamental causes which are responsible for the nature of such properties is lacking. Here, we perform a molecular orbital study of the interactions involved in the hydration scheme of the ions looking particularly into the role of nonadditive effects. Notable differences are found for the cases of Mg2+ and Ca2+.