DFT study on the interaction between monomeric aluminium and chloride ion in aqueous solution

Abstract

The interaction of monomeric aluminium and chloride ion in aqueous solution is investigated by density functional theory (DFT) calculations. The computational results show that it is difficult for Cl⁻ to enter the inner-coordination shell of aluminium complexes by replacing the bound water molecules, independent of pH and the concentration of Cl⁻. However, pH and the concentration of Cl⁻ might influence the conformations, bond lengths and natural charge populations of monomeric aluminium complexes to a given extent. Based on the computed Gibbs energies, pK_a values of various hydrolysis species in the presence and absence of Cl⁻ are evaluated, respectively. It is concluded that pK_a increases with the introduction of Cl⁻.