SYNTHESIS AND PROPERTIES OF POTASSIUM 11-TUNGSTONIOBATE

摘要

The anion of tungstoniobate was synthesized for the first time as KqNbW″O40 2H₂O by the reaction of soluble potassium niobate and porous white tungstic acid in aqueous solution. The structure of the anion may be proposed reasonably to be similar to that of dodecameric anion of paratungstate, resulting from substituting of one WO₆ group in paratungstate anion by one NbO₄ group and leading to the formation of tungstoniobate anion according to the extreme similarity of IR and UV spectra of these two different anions. Potassium 11-tungstoniobate is soluble in wator and unstable in alkaline medium while the structure of the anion may be considered to keep unchanged in acidic medium according to the spectrophotometrical results.