Hydrogen-bonding interactions involving 2-(trifluoromethyl)-1,1,1,3,3,3- hexafluoropropane (1H) and 1- have been quantitatively studied by means of Fourier transform ion cyclotron resonance spectrometry. The existence of the species (1HCl)- and (1H1)- was demonstrated, and their thermodynamic stabilities were determined experimentally and computationally. In addition, some of their structural features were analyzed. © 2009 American Chemical Society.