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.