Linear relationship for acidity and stability in hexaaqua metal ions — density functional studies

Linear correlation between the acidity constant and structural stability in hexaaqua metal ions has been rationalized by applying density functional theory. Six-coordinated aqueous cations of Mg2+, Ca2+, Mn2+, Zn2+, Cd2+, Al3+, Sc3+, Cr3+, Fe3+, Ga3+ and In3+ were investigated. Through local (Vosko–Wilk–Nusair) and nonlocal (Becke–Perdew and Becke–Lee–Yang–Parr) density functional binding energy calculations, the structural stability of hexaaqua metal ions is strongly affected by the cationic valence, electronic configuration and ionic radius of the metallic cations. This complete density functional result has confirmed the existence of a global linear relationship for acidity and stability in both main and transition group hexaaqua metal ions.