Synthesis and spectroscopic characterization of complexes of Cr(III), Cr(VI), Cu(III), Zn(II), Mo(VI), Pd(II), Ag(III), Au(III) and W(VI) with telluric acid

New preparative methods are reported for telluric acid complexes, Na5[Cr(TeO4(OH)2)2(H2O)2], Na6[Zn(TeO4(OH)2)2(H2O)2], Na6[Pd(TeO4(OH)2)2], Na5[M(TeO4(OH)2)2] (M(III) = Cu, Ag, Au) and K 6 TeM 6 ′ O 24 (M′(VI) = Cr, Mo, W). Their structures were characterized on the basis of spectroscopic, crystallographic, magnetic and thermal measurements. The deprotonation constants of telluric acid and the stability constants of the Co(II), Ni(II), Cu(II), Zn(II) and Pd(II) complexes were determined by pH-metric measurements.