Further ESR studies of the cyclic sulphur nitride radical S 3 N 2 + with a Q‐band spectrometer

From measurements made with both Q‐band and X‐band ESR spectrometers on powder samples enriched in 33 S, it has proved possible to establish with improved precision the 33 S hyperfine interaction tensors of the cyclic inorganic free radical 1,2,4,3,5,‐trithiadiazolyl,. The best set of spectral parameters consistent with all of the data presently available is g = (2.0013, 2.0060, 2.0252), a (2 15 N) = (36.4, <0.5, <0.5) MHz, a (2 33 S) = (108.0, −15, −17.0) MHz and a (1 33 S) = (−37.0, 10, 2) MHz, where tensor components are in the order x, y, z and x is the direction perpendicular to the molecular plane. The anisotropic parts of the hyperfine tensors lead to estimates for the unparied spin population in the atomic p x orbitals perpendicular to the atomic plane of 42% (2S), 15% (2N) and (−) 16% (1S). A quadrupolar tensor e 2 Q q = (±32, ∓28, ∓4) MHz determined for the two equivalent 33 S nuclei is consistent with the proposed electronic structure of the free radical.