Higher-Molecular-Weight Polyoxometallate Anions

In general, these structures are built from MO polyhedra and PO4 tetrahedra which share some of their O atoms in common, together with OH, H2O and sometimes other groups. Organic cations and cations of electropositive metals may sit inside these complex polyhedra, or lie between them. 

FIGURE 5.49 Structures of heteropoly cavity anions, (a) (NH4)4(NaP5W30,o) SlHjO viewed down channels of 5-fold symmetry which accommodate Na+. The NH4 lie outside the complex anion of PO4 tetrahedra and WOg octahedra. (b) K28Li5H7P8W4gO,84 92H2O viewed down large channels which accommodate some of the K. Remaining cations lie outside the stucture shown. (Adapted from M.H. Alizadeh et al., JACS, 107, 2662, 1985 R. Contant and A. Teze, IC, 24, 4610,1985.) 

FIGURE 5.50 Structure of the NaMosP4024(OH)7 anion. (Adapted from R.C. Haushalter and F.W. Lai, IC, 

Lanthanide polyoxometallates have potential uses for radionuclide separation and for nuclear 

Various diphosphate/polyoxometallate complex anions have been characterised [102,171], for example 

---