Scheme 1. Schematic Representation Showing the Synthesis of [M(H₂O)₃(GeW₁₀)₂]^n– Starting from the Dilacunary ((TBA)[GeW₁₀] TBA = Tetrabutylammonium) Precursor.

In contrast to the Ln^III system, the addition of H₂O₂ to the reaction mixture is crucial for the successful incorporation of Zr^IV into the POM architecture (M = Ce^III, Nd^III, Gd^III, Er^III, n = 9; Zr^IV, n = 8). Blue and red spheres represent the M- and oxygen ions, respectively. Grey for Ge and yellow polyhedra for {WO₆}.