Abstract The trifluoromethylation reactions of (CF 3) 2 Hg, CF 3 I and (CF 3) 2 Te with cyclohexene, benzene and pyridine are compared under similar conditions. Photochemical as well as thermal reactions result in an increase of the reactivity in the series (CF 3) 2 Hg< CF 3 I⪡(CF 3) 2Te. The yields and the kind of products vary depending on the time of irradiation and the temperature. In all cases the best yields are obtained from the thermal ...