Torsional frequencies have been assigned in the far infra-red and Raman spectra of C2H5Cl, CH3˙ CHCl2, CH2Cl ˙ CH2Cl, CHCl2CH2Cl, CH2Cl ˙ CCl3, CHCl2˙ CHCl2 and CHCl2˙ CCl3. Barrier heights have been calculated for the symmetric top molecules; V3 ranges from 3.3 to 14.2 kcal mole–1. The problem of estimating barriers in asymmetric top molecules is more difficult. Nevertheless, for these molecules, barrier heights ranging from 5.1 to 12.0 kcal mole–1 have been calculated, which are comparable in magnitude to those obtained for the symmetric top molecules.