17O NMR study of aqueous peroxoisopolymolybdate equilibria at lower peroxide/Mo ratios

Abstract

Aqueous peroxomolybdates have been studied using ¹⁷O NMR together with equilibrium measurements and calculations, over a wide range of conditions. Ten peroxo species are identified, mostly in more than one state of protonation. Some are already known in the solid state, or from equilibrium analysis, but structural information is also obtained for MoO₃(HO₂)⁻ and the new or previously tentative species Mo₂O₅(O₂)₂²⁻, H_pMo₇O₂₃(O₂)₂^p−6 and H_pMo₇O₂₃(O₂)^p−6 (p = 0–2). Sites of protonation are identified, as are ¹⁷O resonances from both bidentate and monodentate peroxide. Several oxygen exchange processes are also seen, including a probable dimer–tetramer exchange.