SYNTHESIS AND CHARACTERIZATION OF NEW ALUMINUM AND GALLIUM HETEROPOLY COMPLEXES WITH CHROMIUM, IRON, COBALT OR COPPER-CENTERED UNDECATUNGSTATE LIGAND

Eight aluminium and gallium heteropoly undecatungstometalate complexes of general formula K(n)[M(H2O)-XW11O39].nH2O, where M = Al(III), Ga(III), and X = Cr(III), Fe(III), Co(II) or Cu(II), have been prepared and characterized by elemental analysis, cation exchange i.r., u.v., x-ray powder diffraction and by thermal analysis. The compounds are stable in acidic solution. I.r., u.v. spectra and x-ray diffraction studies show that the structure of the compounds derives from the Keggin structure. Their thermostability is higher than that of the homologous dodecatungstometalates.