for CH 2 F 2 there is no data. Hydration free energies, enthalpies of vaporization and molar volumes, calculated with our parameters for CHF 3 , CH 2 F 2 and CH 3 F, are given in SI Table . Our parameters follow the expected trend of increasingly positive hydration free energy with increasing degree of fluorination, though the hydration free energy for CH 3 F is off by 0.7 kcal mol 1 . Because of the lack of experimental data, we cannot comment on the quality of our parameters for CH 2 F 2 .