1 (99%) all the evidence reported by proponents of either process. We report the preparation and characterization of 10-S-5 sulfurandioxide salt, 1, 5 the first example of an observable analogue to the intermediate postulated to lie along the pathway of associative nucleophilic attack at sulfonyl sulfur. The 10-S-4 sulfuranoxide, 2, 6 analogue of the postulated intermediate in nucleophilic reactions at sulfinyl sulfur was also prepared. The syntheses ...