Halogenomethane derivatives exhibit thermally induced solid¿solid phase transitions before melting that are attributed to the ability to gain rotational degrees of freedom in the crystalline state (orientationally disordered phases) due to the little hindrance for reorientational processes produced by the more or less globular shape of the molecules. The low-temperature phase of CBrCl3 and CBr2Cl2 compounds the molecules were assumed to be disordered so that sites have fractional occupancies of 0.75 and 0.25 for CBrCl3 and 0.5 for CBr2Cl2 for each of Cl and Br atoms, respectively. Below 90 K such an ¿¿occupational disorder¿¿ is frozen giving rise to a glass state and thus, to an excess in the vibrational density of states. This proposal concerns the study of the anomalous enhanced vibrational density of states in the low-frequency spectral range over the predicted for a homogeneous solid