Abstract Thallic trifluoromethanesulfonate has been prepared by reaction of trifluoromethanesulfonic acid with either thallic oxide or solutions of thallic trifluoroacetate in trifluoroacetic acid, and has been isolated as the trihydrate on crystallization fromnitromethane. The polyfluoroarenes, p-CH 3 OC 6 F 4 H, p-CH 3 C 6 F 4 H, mH 2 C 6 F 4, oH 2 C 6 F 4, pH 2 C 6 F 4, C 6 F 5 H, 1, 3, 5-F 3 C 6 H 3 or 1, 2, 4-F 3 C 6 H 3, have ...