Electronic Structure of Sulfate, Thiosulfate, and Related Ions. II. ESR Spectra of SO4− and S2O3−

The radical ions SO4− and S2O3−, trapped in γ-irradiated K2SO4 and Na2S2O3·5H2O crystals, respectively, have been identified by their ESR spectra. In the preceding paper molecular orbital calculations were described the results of which predict a ···1t163t262a1, 2A1 (symmetry Td) configuration for SO4− and a ···5e45a1, 2A1 (symmetry C3v) configuration for S2O3−. The ESR data show that in the K2SO4 crystal the symmetry of SO4− is no higher than C2v and so correlation with the predicted configuration was inconclusive. In the case of S2O3−, however, the spectral parameters possessed axial symmetry, the ···e4a1, 2A1 configuration being confirmed by the nature of the hyperfine and g tensors.