The refractive indices of perdeuterated hydrocarbons n-hexane-d(14), h
eptane-d(16), and octane-d(18), benzene-d(6), toluene-d(8), and ethylb
enzene-d(10) have been measured at room temperature at five different
wavelengths. The polarizabilities of these compounds have been compute
d as a function of wavelength using the Lorentz-Lorenz equation and at
infinite wavelength using the Cauchy equation. In all cases, the pola
rizabilities of the deuterated compounds are less than the correspondi
ng nondeuterated compounds.