The relative fluoride donor ability: C 6 F 5 BrF 2 >C 6 F 5 IF 2 >C 6 F 5 IF 4 was outlined from reactions with Lewis acids of graduated strength in different solvents. Fluoride abstraction from C 6 F 5 HalF 2 with BF 3 ·NCCH 3 in acetonitrile (donor solvent) led to [C 6 F 5 HalF·(NCCH 3 ) n ][BF 4 ]. The attempted generation of [C 6 F 5 BrF] + from C 6 F 5 BrF 2 and anhydrous HF or BF 3 in weakly coordinating SO 2 ClF gave C 6 F 5 Br besides bromoperfluorocycloalkenes C 6 BrF 7 and 1-BrC 6 F 9 . In reactions of C 6 F 5 IF 2 with SbF 5 in SO 2 ClF the primary observed intermediate ( 19 F NMR, below 0°C) was the 4-iodo-1,1,2,3,5,6-hexafluorobenzenium cation, which converted into C 6 F 5 I and 1-IC 6 F 9 at 20°C. The reaction of C 6 F 5 IF 4 with SbF 5 in SO 2 ClF below −20°C gave the cation [C 6 F 5 IF 3 ] + which decomposed at 20°C to C 6 F 5 I, 1-iodoperfluorocyclohexene, and iodoperfluorocyclohexane. Principally, the related perfluoroalkyl compound C 6 F 13 IF 4 showed a different type of products in the fast reaction with AsF 5 in CCl 3 F (−60°C) which resulted in C 6 F 14 . Intermediate and final products of C 6 F 5 HalF n−1 (n=3, 5) with Lewis acids were characterized by NMR in solution. Stable solid products were isolated and analytically characterized.