The paper presents physical property measurements for 24 fluorinated propane and butane derivatives and one fluorinated ether which include melting point, boiling point, vapor pressure below the boiling point, heat of vaporization at the boiling point, critical properties (temperature and density), and liquid-phase heat capacities at 40 C. Measured vapor pressures are reported to the critical temperature for four of the compounds: HFC-227ea, HFC-245cb, HFC-236ea, and HFE-125a. These measured data, combined with estimated vapor-phase densities, heat capacities, and vapor pressures, may be used to evaluate the potentials of these chemicals as alternative refrigerants. Modified corresponding states methods, using HFC-134a as a reference fluid, are presented as a way to obtain the needed estimated data, and the accuracy of these methods is judged by comparisons with measured data.