Free radicals in γ-irradiated disodium succinate. Part 1. Monoclinic crystals

Crystals of disodium succinate have two distinct modifications, monoclinic and triclinic. These were recognized by electron spin resonance (e.s.r.) studies of. the free radicals produced by γ-irradiation. In the monoclinic crystals, e.s.r. spectra and radiation processes appear similar to those observed in γ- (or x-) irradiated succinic acid. The situation in triclinic crystals is more complex (see Part 2). In monoclinic crystals irradiated at 77 °K, two types of radical coexist. They were identified as − O 2 CCH 2 CH 2 ĊO 2 2− , 1, together with a distorted conformation of the radical − O 2 C(ĊHCH 2 )*CO 2 − , 2. On warming to room temperature the former species disappears while the latter changes irreversibly to a stable conformation − O 2 CĊHCH 2 CO 2 − , 3.