The Raman and far-infrared spectra of crystalline nitrometbane and its fully deuterated analogue were recorded over the frequency range 20400 cm-' and at temperatures between 20 and 150 K. In the spectra of CH,NO, , 15 of the 21 Raman-and 13 of the 15 infrared-active lattice modes predicted by group theory were observed. The corresponding numbers for CD,NO, were 17 and 14, respectively. Isotopic frequency shifts together with inertia and intensity arguments were used to assign the peaks. Frequency coincidences in the two types of spectra are indicative of a noa-centrosymmetric cell. Several features are attributed to the torsional mode or interactions with this mode.