Ethylene, propylene, cis-butene-2, trans-butene-2, ethane, propane, and n-butane were added to xenon at 168 and 192 K. At concentrations up to 4 mol%, electrons were scattered by one hydrocarbon molecule at a time and a gas phase model was used to estimate the scattering cross sections. The values for thermal electrons were, in Å2: ethane, 2.7; propane, 4.6; n-butane, 7.2; ethylene, 4.7; propylene, 5.4; cis-butene-2, 7.4; trans-butene-2, 9.4. The scattering cross sections of the hydrocarbons dissolved in liquid xenon were about half of those in the gas phase, where comparisons could be made.The mobility of electrons in pure xenon decreases with increasing electric field strength, due to heating of the electrons by the field. Addition of a small amount of hydrocarbon increases the mobility at high fields, eightfold by 4% of ethylene, propylene, or cis-butene-2 at 23.4 kV/cm and 192 K. The scattering cross sections of the hydrocarbons are two orders of magnitude larger than the effective cross section of liquid xenon, and the collisions with the hydrocarbons tend to prevent the electrons from becoming heated.Electrons begin to form localized states in solutions containing 10 mol% hydrocarbon, or 20 mol% in the case of ethane. The mobility decreases approximately exponentially with concentration above these thresholds. The values of μ0 for these exponential regions reflect the different scattering coefficients of the hydrocarbons: μ = μ0 exp (−Eμ/RT). The values of Eμ increase with molecular size in a series, and are greater for olefins than for alkanes. For the C2 and C3 hydrocarbons Eμ increases linearly with the mol fraction of hydrocarbon. cis-Butene-2 shows anomalous behaviour, as found earlier for electrons in the pure compound.