单核Zn(Ⅱ)水合和水解形态的量子化学计算

利用量子化学计算气相中锌离子各种水合和水解形态的几何结构、电荷分布以及水合和水解反应的Gibbs自由能变和焓变．结果表明，除了水合锌离子外，锌离子各种水解络合物的配位数均小于6；对于深度水解产物Zn（OH）3^-和Zn（OH）4^2-，内层无水分子的键合．水合作用和水解作用互相抑制，水合作用阻碍了水解产物进一步水解（Zn（OH）2除外），水解作用使得水合变得困难．内层键合水分子数的增加降低了水合形态中Zn上的电荷，使得水解形态Zn上的电荷升高．

STUDIES OF MONONUCLEAR ZINC SPECIES OF HYDRATION AND HYDROLYSIS BY QUANTUM CHEMICAL CALCULATIONS

Optimal geometries, charge distributions, changes of Gibbs free energy, entropie s and enthalpies of hydration and hydrolysis reactions for mononuclear speci es of Zn~2 including hydrated and hydrolysis complexes were investigat ed in the gas phase using quantum chemical calculations. The coordination number of hydrolysis complexes of zinc was less than 6 except hydrated ion. For the hi gh degree of hydrolysis products, Zn(OH)~-_3 and Zn( OH)~2-_4,there were no water molecules in the inner-sphere. Hydra tion and hydrolysis processes restrained each other. Hydration made hydrolysis p roducts (except Zn(OH)_2) difficult to hydrolyze further, while hydrolysis process cumbered hydration reaction. The increase of the inner -sphere water molecules decreased the charge of Zinc for hydrated ions whil e increased the charge of zinc for hydrolysis complexes. The results are importa nt to understand aquatic environmental behaviors of zinc.