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.