Fluorine reagents, hexafluroacetone, trifluoroacetic anhydride, and trifluoroacetyl chloride have been previously used for /sup 19/F NMR for determination of organic structure and functionality. A new fluorine reagent, trifluoromethanesulfonyl chloride, is discussed in this paper. The reagent not only yields sulfonation products with active hydrogen containing compounds but also forms stable compounds with tertiary nitrogen bases, presumably by a Lewis acid-Lewis base reaction. The /sup 19/F chemical shift for the trifluoromethanesulfonyl derivatives of aliphatic alcohols, primary, secondary, and tertiary; phenols; primary and secondary amines; and pyrollic-ring compounds are presented and discussed in relation to structural effects. No evidence of reaction of the trifluoromethanesulfonyl chloride acting as a chlorinating reagent was reported.