Ultra-facile mechanochemical synthesis of sodium and silver metaperiodate at room temperature

Ultra-facile mechanochemical synthesis of single phase metaperiodates, AgIO₄ and NaIO₄, was achieved in a matter of minutes by gentle grinding of AgNO₃ or NaNO₃ with orthoperiodic acid, H₅IO₆, at room temperature. The reaction mechanism is hypothesised to involve the equilibrium between H₅IO₆ and HIO₄, effected under the tribological conditions of grinding, leading to the release of H₂O, production of metaperiodate species, and formation of the products by dissolution – precipitation, as evidenced by powder X-ray diffraction and Scanning Electron Microscopy data. Time resolved X-ray diffraction demonstrated that initial grinding of reagents, over 60 s, is sufficient to initiate the reaction. The mechanochemical method presented here meets the need for a simple, safe, scalable and sustainable approach to the synthesis of sodium and silver metaperiodates.