Cation mobilities μ+ in liquid hydrocarbons do not obey Walden’s rule (μ+∝η−1.0). Their relationship with the solvent viscosity η is μ+∝η−1.2±0.1, as found earlier for ions in ethers. Ion migration in liquids made up of nonspherelike molecules is more closely linked to solvent molecular rotation than to shear viscosity. Dipole (permanent or induced) rotation is required during ionic displacement to minimize changes in polarization energy. Diffusion coefficients D of ions in liquid n-hexane are twofold lower than the self-diffusion coefficient of the hexane molecules over most of the liquid range. There is a cusp in the ratio D (molecule)/D (ion) at the critical point. The lower diffusion coefficient of the ion is attributed to its probable dimeric size and to electrostrictive drag. Mobilities in the critical fluids are 4.3, 5.0, and 5.6 (10−3 cm2/Vs) in cyclopentane, cyclohexane, and n-hexane, respectively. In the gas phase along the gas–liquid coexistence curve, the density normalized mobilities μ+n are independent of n up to n/nc?0.8, then increase with n. The increase continues through the critical region and in the liquid phase up to n/nc?1.5; at higher densities μ+n decreases. The ion scattering cross sections of the low density gases have the same velocity dependence in cyclopentane, cyclohexane, and -hexane: σv=Aαv−α, α=2.0. Assuming the ions to be dimeric, the respective values of Aα are 0.01, 0.79, and 1.07 (10−4 cm4 s−2). The scattering potential is more complex than that due to the simple charge induced dipole interaction. The temperature coefficient of μ+ increases with n, probably due to clustering of molecules about the ions at temperatures near the coexistence curve.