HF, hydrofluoric acid, is a weak acid, meaning it doesn't come apart well in water. It is, however, one of the most corrosive agents known, even reacting with glass, and must therefore be stored in Teflon, a fluorine-containing plastic.
One of the isotopes of fluorine, 18F (which is essentially Fluorine plus twice as many neutrons) has a halflife of something like a couple millionths of a second. It is one of the more significant sources of positrons. Positrons, as in antimatter, as in electron plus positron go boom make gamma rays.
My question, for anyone still paying attention, is: assuming 18F is metastable at a certain pressure-temperature condition (this IS science fiction), how would the reactivity of an 18F-enriched solution of HF compare to normal HF? Would H-18F be THAT much more reactive? Or would the reactivity be changed in a different way?