The reaction of hydrated iodide I(H2O)− with ozone: a new route to IO2− products

We report on an experimental characterization of the isolated reaction of hydrated iodide I(H2O)− with ozone O3 at room temperature performed using a radio-frequency ion trap combined with a quadrupole mass spectrometer. Contrary to the oxidation reaction of the bare I− ion, the hydrated iodide I(H2O)− primarily reacts to form I− and IO2− with significant absolute reaction rate constants of 2.0 ± 0.3 × 10−10 cm3 molecule−1 s−1 and 2.5 ± 0.3 × 10−10 cm3 molecule−1 s−1 while direct pathways to IO− and IO3− are much weaker. Quantum chemical calculations indicate that in aqueous phase and for atmospherically relevant temperatures, the presence of hydrated iodides are favored over bare I− ions, thus suggesting that the chemistry of the hydrated ions is relevant for understanding and modeling atmospheric processes at the air–water interface.