Many Raman lines of liquid n-paraffins were found to disappear completely on solidification. This is due to the fact that while there are several rotational isomers in the liquid state, there is only one in the solid state. The molecular form corresponding to the latter is the planar zigzag configuration, hence all the Raman lines of solid n-paraffins must be assigned to the Raman-active frequencies of this configuration. It was shown that such is actually the case by the present calculation made for skeletal frequencies.