Electron spin resonance studies have been made of the radicals produced by electron irradiation of sodium chlorodifluoroacetate at room temperature. Three sets ofmiddot;CF2COOminus;radicals are observed, each with a somewhat different conformation or local environment in the crystal lattice, but each with nearly the same principal values of the hyperfine splitting tensor for the two equivalent agr;hyphen;fluorine atoms. One radical occupies two sets of nonequivalent positions characteristic of the space group. A second radical also shows site splitting in the ESR spectrum, but the maximum separation is only about 14 G since the maximum principal component of the hyperfine splitting tensor lies nearly parallel to theaaxis of the monoclinic unit cell and one of the smaller principal values is nearly parallel tob. A third radical has its maximum principal hyperfine splitting direction perpendicular toband minimum value parallel tobso that no site splitting is observed; however, triplet superhyperfine structure from interaction with two equivalent nuclei of spin onehyphen;half is present. The hyperfine coupling tensors have been evaluated and the structures of the radicals discussed. The radicals undergo some reorientation in the lattice on cooling from 300 to 77deg;K. Incomplete data formiddot;,13CF2COOminus;indicate that these radicals are probably nonplanar with the unpaired electron in an orbital with somescharacter. Exposure to air or gaseous oxygen converts all these to peroxide radicals, each of which gives only a single ESR line.
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