Results.-We have found that the addition of thiols and more particularly trifluoromethancthiol to tetrafluoroethylene, chlorotrifluoroethyltne, trifluoroethylene, hexafluoropropylene, 1, l- difluoroethylene and trifluorovinyl methyl ether (all terminal fluoroolcfins) proceeds smoothly under the influence of ultraviolet radiation or X-rays. With two olefins, hexafluoropropene and trifluoroethylene, both possible 1: 1 adducts were obtained. The results are ...