KNbO3 and powdery white tungstic acid in aqueous solution The structure of the anion may be proposed reasonably to be similar to that of [W12O40H2]6-, resulting from substituting of 1 WO6 group by 1 NbO6 group and giving [NbW11O40H2]7- according to the extreme similarity of IR and Raman spectra of these 2 different anions.

Key words: INFRARED SPECTROPHOTOMETRY, HETEROPOLYACID, POTASSIUM COMPOUNDS, NIOBATE P, TUNGSTATE P, WHITE TUNGESTIC ACID, RAMAN SPECTROMETRY