Contrasting ion-association behaviour of Ta and Nb polyoxometalates†
Abstract
Small-angle X-ray scattering (SAXS) studies of aqueous [Ta6O19]8− compared to prior studies of aqueous [Nb6O19]8− reveals key differences in behaviour, which is likely at the root of the difficultly in developing polyoxotantalate chemistry. Specifically, where contact ion-pairing dominates between [Nb6O19]8− and its counterions, solvent-separated ion-pairing between [Ta6O19]8− and its counterions has been unveiled in the current study.