Dawson结构硫钼杂多阴离子的电子结构

使用第一原理密度泛函理论中的离散变分方法（DFT-DVM）对（S2Mo18O62）4-的电子结构进行了理论计算，并与Keggin结构（SMo12O40）2-的电子结构作了比较分析，结果表明，（S2Mo18O62）中的电子离域地分布在整个阴离子骨架中，但极位和赤道位原子的电荷分布有明显差异。端氧与Mo之间的键均较强，中心氧与Mo之间形成的键最弱。（S2Mo18O62）4-的化学行为的活性中心是赤道位钼Moe、极位端氧Opt、极位共顶桥氧Opea、赤道位端氧Oet和赤道位共边桥氧Oeb。与（SMo12O40）2-相比，（S2Mo18O62）4-的稳定性和氧化性均较弱。但在两种类型的硫钼杂多阴离子中，Mo对其氧化性的产生起了重要的作用。

The Electronic Structures of Dawson-type Heteropoly Anion Molybdodisulfat

The electronic structures of Dawson anion(S2Mo18O62)4- have been calculated by the discrete variational method coupled with the first principal density functional theory(DFT-DVM).And the comparison with Keggin anion(SMo12O40)2- has been made.The results show that the electrons delocalize around the all anion.But the difference of the electronic distributi on of polar and equator sites exists.The bonds which formed by terminal oxygen and Mo are stronger and the bonds formed by centre oxygen and Mo are weakest.The active centers of chemical actions are Moe(which is at the equator sites),Opt,Opea(at polar sites)Oet,Oeb,,,(at equator sites).Compared with (SMo12O40)2-,the stability and oxidation ability of (S2Mo18O62)4- are weaker.To the two anions,the Molybdenum atoms pay an important role in their redox effects.