ESR of diphenylantimony radical in a triphenylantimony single crystal

Ultraviolet irradiation of a single crystal of triphenylantimony produces an antimony centered radical with an anisotropic 121Sb coupling having principal absolute values of 704, 352, and 352 MHz and a g tensor with the same principal axis as the hyperfine interaction and components of 1.998, 2.045, and 2.065. This radical has been assigned to the diphenyl antimony radical with approximately zero s and 0.7 p character. The linewidth of the spectra are consistent with unresolved hyperfine structure due to spin density delocalized on the phenyl rings.