Tungsten polyoxotungstate

The metal substituted polyoxotungstates are, like the lacunary and the parent Keggin anions, able to reversibly accept a certain number of electrons (up to six) on the tungsten atoms. Besides that, oxidation or reduction of the metal M may occur. Electrochemical techniques, like polarography " - and cyclic voltammetry, " have proved to be quite useful for the identification and characterisation of these anions. 

Muller and Ermler et al. have observed various types of polynuclear tungsten oxide clusters in the cavity of aMoAV-storage (MoAVSto) protein [70], i.e., five types of polyoxotungstates such as W3, W, W, W, and, are formed in the pockets of MoAVSto protein. The Wj cluster shown in Fig. 7e consists of ten O atoms and N atoms of three Hisl39 in different subunits, described as WjOj HjNj. 

Cross, W. B. and Parkin, I. P. (2003) Aerosol assisted chemical vapour deposition of tungsten oxide films from polyoxotungstate precursors active photocatalysts. Chemical Communications, 1696-7. 

Villanneau, R., Carabineiro, H., Carrier, X., et al. (2004). Synthesis and Characterization of Zr(IV) Polyoxotungstates as Molecular Analogues of Zirconia-Supported Tungsten Catalysts, J. Phys. Chem. B, 108, pp. 12465-12471. 

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