AbstractInfrared and Raman spectra are reported for polycrystalline perchloro‐[4]‐radialene and for solutions in CCl4and CS2. An earlier X‐ray structure determination by van Remoortere and Boer has shown that in the crystal the molecular symmetry is almostD2d(puckered ring), but is slightly distorted toC2. This distortion was attributed to crystal packing forces. The vibrational spectrum does not show the distortion. The spectra are essentially the same for polycrystalline solid as for solution, and are completely compatible withD2din both states. Assignments are made for a few of the modes where evidence warrants it. Some observations are also made about the mass spectrum, which has a rich structure because of the many isotopic sp