Hydrogen/deuterium exchange was observed by H-2-NMR spectroscopy for the long-lived 2-propyl cation when treated with DF in SbF5/SO2ClF at -78 degrees C. As under long-lived stable ion conditions at low temperatures no deprotonation equilibria exist for alkyl cations, protio (deuterio) solvation involving the intermediacy of the protio(deuterio)-2-propyl dication is suggested to account for the exchange. Ab initio calculations at the MP4SDTQ/6-31G**//MP2(FU)/6-31G** level show the protio-2-propyl dication, a gitonic (proximal) dication (as contrasted with usual distonic (distant) dications), to be a remarkably stable minimum structure and support the suggested mechanism for the observed isotopic scrambling.