Formation of large clusters in the reaction of lanthanide cations with heptamolybdate

A series of new lanthanide polyoxomolybdates was synthesised by reaction of lanthanide cations with the heptamolybdate anion (Mo7O24)(6-). The heteropolyanions [Ln(4)(MoO4)(H2O)(16)(Mo7O24)4](14-) (Ln = La-III, Ce-III, Pr-III, Sm-III, Gd-III) were isolated as either their ammonium or tetramethylammonium salts and characterised by X-ray structure analysis, energy dispersive X-ray fluorescence analysis, and IR and Raman spectroscopy. The central [Ln(4)(MoO4)(H2O)(16)](10+) core of the anion is coordinated by four heptamolybdate groups. Each Ln(III) atom in the core exhibits ninefold coordination by oxygen atoms belonging to H2O, (MoO4)(2-) and (Mo7O24)(6-) units; the central molybdenum atom is coordinated tetrahedrally by four oxygen atoms. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004).