| Abstract
| - Optimal geometries, charge distributions, bond analysis, changes of Gibbs free energy, entropies and enthalpiesof hydration, and hydrolysis reactions for mononuclear species of Zn2+ including hydrated and hydrolysiscomplexes were investigated using quantum chemical calculations in the gas phase. Optimized geometricalstructures showed that the stable hydrated and hydrolysis zinc species without outer-sphere water moleculeswere Zn(H2O)62+, Zn(OH)(H2O)3+, Zn(OH)2(H2O)2, Zn(OH)3-, and Zn(OH)42-. Results of NPA (NaturalPopulation Analysis) indicated that the charge on the Zn atom of the hydrated ions decreased but the chargeon the zinc atom of the hydrolysis species increased with the increase of inner-sphere water molecules. NBO(Natural Bond Orbital) analyses demonstrated that hydrated and hydrolysis species of zinc were mainlyelectrostatic bonding compounds. Calculations of reaction energies indicated that inner-sphere water moleculesbecame more unfavorable as the hydrolysis increased. Stepwise hydrolysis equilibrium constants decreasedsuccessively and the order remained unchanged when the inner-sphere dehydration occurred.
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