The products of hexafluorobutadiene sulfotrioxidation were identified by 19F NMR. The major products are hexafluoro-1-butene-3,4-β-sultone, hexafluoro-2-butene-1,4-sultone, hexafluoro-1-butene-3,4-pyrosultone, and hexafluoro-2-buten-1,4-diyl sulfate.