ISOLATION AND PROPERTIES OF MOLYBDE-NUM SERIES OF HETEROPOLY BLUE WITH KEGGIN STRUCTURE

The present paper reports the methods for preparing and isolating 8 kinds of 1:12 molyb-denum series of heteropoly blue complexes KyHzXMo22O40·nH2O （X=Si, P, As, Ge）. Theproducts were characterized by elemental analyses, potential titration, polarograms, cyclicvoltammetry, IR spectra, visible--UV spectra, X--ray powder diffraction, XPS and 31P NMR.The single crystal structure of 4-electron molybdenum--silicon heteropoly blue was measuredand the positions of reduced molybdenum atoms were determined, i.e. they were located atMo（3）, Mo（7）, Mo（8） and Mo（10）. The experimental results show that the heteropoly blueremains Keggin structure. ESR spectra of heteropoly blue solids were first studied, fromwhich it was found that the delocalization extent of 2-electron heteropoly blue and 4--electronheteropoly blue is smaller than that of 1-electron heteropoly blue. The study of thermal prop-erties shows that the thermal stability increases with the increase of the reduction extentof heteropoly blue. Th