Figures provide several clues regarding the mechanism of this intriguing S-S metathesis reaction. First, the high rates in polar, aprotic solvents suggest a rate determining step involving a polar intermediate or transition state. Second, the extraordinary selectivity for trisulfide products means that thiolate or thiyl radical intermediates are unlikely because such species lead to the formation of other polysulfides such as disulfides and tetrasulfides. The lack of a significant EPR signal for the reaction is consistent with a non-radical pathway. Computational insights also predict that the formation of thiyl radicals or thiolate anions would lead to mixtures of disulfides, trisulfides, and tetrasulfides under the reaction conditions (S194-S198), but such mixtures are not observed. Third, the reaction seems to be unique to linear trisulfides, as the corresponding process does not occur with either disulfides, tetrasulfides, or 5-member cyclic trisulfides under the conditions examined.