Evidence of stable hydroxyl radicals and other oxygen radical species generated by interaction of hydrogen peroxide with magnesium oxide

Three distinct radical species are formed and stabilized in the solid matrix upon the treatment of magnesium oxide with hydrogen peroxide in aqueous solution leading to the transformation of the solid into magnesium peroxide. The species in question are the O 2 - superoxide radical ion, the O - radical ion, and the OH hydroxyl radical. The latter radical is characterized by orthorhombic g and A tensors whose principal values, due to the ionicity of the trapping matrix, are slightly different from those previously observed for OH in irradiated ice or similar systems. In comparison to the OH radical trapped in ice, the hydroxyl radical observed in the present case (as well as the two companion radicals) is stable up to 473 K