A new solubility parameter, SP, for hydrofluorocarbons (HFCs) has been developed (SP = 1.175 ln(np) + 0.025H - 0.063F - 0.028α - 0.018β where np depends on the molar volume and the molar refractivity; H and F are the number of hydrogens and fluorines, respectively, in the molecule; and α and β are the respective numbers of H-C-F and H-C-C-F connections).Values of SP have been used to predict if an HFC would be a good solvent for various hydrocarbons at 25 deg C.Within an isomeric HFC family, the individual HFCs having the greatest solvency for hydrocarbons were those having the maximum separation of fluorines from hydrogens.Hildebrand solubility parameters, δ, are compared with the semi-empirical SP values.Syntheses for 10 new compounds are given: 3,3,4,4,5,5,6,6,7,7-decafluorononane, 1,1,1,2-tetrafluoro-2-(trifluoromethyl)-3-methylbutane, 1,1,1,2,2-pentafluoro-3-methylbutane, 1,1,1,2,2,3,3,4,4-nonafluoro-5-methylhexane, 1,1,1,2,2,3,3,4,4-nonafluoroheptane, 1,1,1,2-tetrafluoro-2-(trifluoromethyl)butane, 1,1,1-trifluoro-3-(trifluoromethyl)butane, 1,1,1,2,2,3,3,5-octafluorohexane, 1,1,1,2,2-pentahydroperfluorooctane and 1,1,1,2,2-pentahydroperfluorodecane.