Sodium a-nonatungstosilicate

Sodium nonatungstosilicate is a white solid, which is slightly soluble in water. The solution is metastable at all pH values, but it changes slowly. The best characterization is polarography in 1 M sodium acetate-1 M acetic acid buffer The polarogram shows only one four-electron wave with 1/2 = — 0.80 V versus SCE. The polyanion can be characterized in the solid state by its IR spectrum (KBr pellet, cm ) 985, 940(sh), 930, 865, 848(sh), 808, 712, 552, 530, 490(sh), 435, 373, and 335. 

The preparation of the lacunary sodium nonatungstosilicate is dependent on adding an acid solution to the mixture of tungstate and silicate ions in a manner such that the aggregation process favors formation of the lacunary structure. Although the preparation described here (based on the previously reported synthesis) produces impure material (by elemental analysis), this... 

---