AbstractThe title reaction gave three known compounds (2, 3 and 4) and two new compounds, CH3SCH2(CF2)2H (5) and I(CF2)2O(CF2)2SO3−S+(CH3)3(6). The structure of 6 was confirmed by X‐ray diffraction analysis. The crystals of 6 belong to monoclinic space group P21/C witha= 9.399,b= 15.651,c=10.934Å, β = 94.80° andz= 4. The structure was solved by heavy‐atom method and refined by block‐diagonal matrix least‐squares procedure to a finalRof 0.054 for 1999 independent observed reflexions.The SC bonds around the sulphur atom in trimethylsulphonium are pyramidal with the bond lengths of 1.814 Å, 1.800Å and 1.818 Å and the bond angles C‐S‐C of 101.06°, 101.52° and 102.53°. The distances of the sulphur atom in trimethylsulphonium to three oxygen atoms in the sulphonate radical are 3.79 Å, 3.64 Å and 3.34 Å respectively. These distances are out of the range of the normal S‐O bond length. The structure consists of trimethylsulphonium cations and 5‐iodo‐3‐oxa