Radiolysis of frozen solutions containing oxybromine anions

Abstract

The radiolysis of oxybromine-anions (BrO^–_n, n= 1–4) and ClO^–₄ in glassy and polycrystalline aqueous solutions has been investigated by e.s.r. BrO₂ is the main product in BrO^–₃ and BrO^–₂ solutions. The thermal stability of BrO₂ varied with the structure and composition of the solution. The e.s.r. spectrum of BrO₂ in aqueous solutions has been simulated with data for BrO₂ in single crystals. BrO was not detected in BrO^–₂ or BrO^– solutions. ClO₃, ClO₄, and ClO^2–₄ were identified in irradiated polycrystalline KClO₄ solutions, but these radicals were not observed in glassy or polycrystalline NaClO₄ solutions, polycrystalline CsClO₄ solutions or in 10 M NaOH solutions containing 0.1 M KClO₄. KBrO₄ solutions behaved similarly to KClO₄ solutions. KBrO₄ reacts with electrons in glassy 10 M NaOH solutions but no bromine-containing radicals are observed. The radicals observed in irradiated polycrystalline KClO₄ and KBrO₄ solutions are assumed to arise from reactions between the water radicals and precipitated salts. Effects of precipitation are also observed in polycrystalline solutions saturated with NaBrO₃ or KBrO₃.