Intermediates in the oxidation of azide ion in acidic solutions

Radiolytic oxidation of azide ion in acidic solutions partially occurs via production of a relatively unreactive intermediate which has a lifetime of ∼10 μs but which decays into azide radical by reaction with proton donors. From chemical arguments this intermediate is identified as the HN₃^-· radical anion produced by attachment of e_aq^- to hydrazoic acid. As with N₂O, the reducing entity produced in radiolysis, e_aq^-, is converted into an oxidizing species, N₃·, with a delay controlled by the rate of reaction of HN₃^-· with proton donors. This delay must be taken into account in studies of secondary oxidation processes, particularly in acidic solutions at high solute concentrations where reaction with substrates occurs at submicrosecond times.