Heteropolytungstates with Unsaturated Heteropolyanions

The UV absorption spectrum is similar to that of the unsaturated heteropolyanion K 0[p2W,7O6 ], but it shows absorption maxima that are less distinct and that are shifted to lower energies (39,690 and 49,480 cm-1)- The IR spectrum shows absorption maxima at 750, 862, and 956 cm 1. The splitting of the band, attributed to the P—O bond, occurs at 1038 and 1092 cm 1. Salts containing other cations may be obtained by double-exchange reactions in aqueous medium. As with other compounds of this class, the Th(IV) heteropolytungstate has the Dawson structure. 

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