Positive ion chemistry of elemental fluorine

F-2(.+) ions have been generated in the external ion source of a FT-ICR mass spectrometer, and their reactivity with a choice of neutrals, ranging from noble gases to polyatomic molecules, has been investigated. With the exception of He and Ne, all neutrals react with F-2(.+) at the collision controlled limit, yielding predominantly electron transfer and fragmentation products. Noteworthy, a formal F+ transfer process takes place from the reaction of F-2(.+) With Ar, among the noble gases, and with CO and N-2, among diatomic molecules. The unimolecular and bimolecular reactivity of F2H+, obtained from the F-2(.+) reaction with H-2, allowed the proton affinity of elemental fluorine (PA = 79 +/- 5 kcal mol(-1)) ro be experimentally derived.