Synthesis and structure of a novel type of polyoxomolybdate lanthanide complex:: [(Ln(H2O)6)2(TeMo6O24)] (Ln = Ho, Yb)

The new polyoxomolybdates [(Ho(H2O)(6))(2)(TeMo6O24)] center dot 10 H2O (1) and [(Yb(H2O)(6))(2)(TeMo6O24)] center dot 10 H2O (2) were prepared from aqueous solution by reaction of telluric acid, potassium molybdate and holmium chloride and ytterbium chloride, respectively. They were characterized by X-ray structure analysis, energy dispersive X-ray fluorescence analysis and IR spectroscopy. Both compounds contain the Anderson type anion (TeMo6O24)(6-) and trivalent lanthanide atoms which achieve eightfold coordination by two terminal oxygen atoms of the (TeMo6O24)6- anion and six crystal water molecules. While all known Ln/(TeMo6O24)(6-) Compounds contain infinite one-dimensional chains in which the (TeMo6O24)6- anions are linked by rare earth cations, the neutral molecular [(Ln(H2O)(6))(2)(TeMo6O24)] complexes in 1 and 2 are only connected via hydrogen bonds.