| Abstract
| - The dihydroxylamine radical anion (HNO2-•, with the H atom on the nitrogen atom) is produced by thereaction of H atoms in the pulse radiolysis of nitrite solutions and decays in water with a rate constant of 5.0× 103 s-1. Its absorption spectrum has a maximum at 270 nm with molar absorptivity of 2.8 × 103 M-1cm-1. The decay of HNO2-• is catalyzed by both acids and bases. The hydronitrite radical (NO22-•) producedby the reaction of eaq- with nitrite exhibits no absorption spectrum between 270 and 550 nm. It is muchshorter-lived than HNO2-•, disappearing at 1.6 × 106 s-1 without generating any HNO2-•. Neither radicalspecies has any observable pKa's, but the pKa for HNO2-• has been estimated to be lower than 9.3 from therate data on the hydroxide-catalyzed decomposition of this radical. Both HNO2-• and NO22-• reduce methylviologen, and the reduction by HNO2-• has been used to measure its yield, which is found to be 0.63 radicalsper 100 eV. Thus, the production of HNO2-• by H atoms is quantitative. Collectively, these data represent amajor revision of the reductive radiation chemistry of nitrite.
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