The chloromethyl group (—CH2Cl) attached to a normal hydrocarbon chain gives rise to two characteristic Raman bands near 660 and 730 cm−1. The band at 660 cm−1, which is very intense, is assigned to a stretching mode of the C-Cl linkage when the chlorine atom is trans to a hydrogen atom. The less intense peak at 730 cm−1 is assigned to the same mode of the rotational isomer with the chlorine atom trans to a carbon atom. These assignments are consistent with those reported in infrared studies. In contrast to almost equal intensities for both bands in the infrared, the band at 660 cm−1 proved to be the strongest by far in Raman spectra.
