LINEAR RELATIONSHIP FOR ACIDITY AND STABILITY IN HEXAAQUA METAL-IONS - DENSITY-FUNCTIONAL STUDIES

Linear correlation between the acidity constant and structural stabili ty in hexaaqua metal ions has: been rationalized by applying density f unctional theory. Six-coordinated aqueous cations of Mg2+, Ca2+, Mn2+, Zn2+, Cd2+, Al3+, Sc3+, Cr3+ Fe3+, Ga3+ and In3+ were investigated. T hrough local (Vosko-Wilk-Nusair) and nonlocal (Becke-Perdew and Becke- Lee-Yang-Parr) density functional binding energy calculations, the str uctural stability of hexaaqua metal ions is strongly affected by the c ationic valence, electronic configuration and ionic radius of the meta llic cations. This complete density functional result has confirmed th e existence of a global linear relationship for acidity and stability in both main and transition group hexaaqua metal ions. (C) 1998 Elsevi er Science B.V.