AbstractTetrachlorocyclopropene, C3Cl4, is converted into C3Br4by treatment with BBr3. Use of less than the stoichiometric amount of BBr3leads to mixed halides C3ClnBr4‐nwhich are identified and investigated by Raman and13C NMR spectroscopy. The addition of Br2to C3Cl4yields both the isomerscis‐ andtrans‐1,2‐dibromotetrachlorocyclopropane in equal quantities; the vibrational spectra are reported and partially assigned. Raman and13C NMR of other mixed halides of cyclopropane, C3ClnBr6‐nare discussed. A35Cl/37Cl isotope effect is detected on the carbon chemical shift of C3Cl6I2fails to react with C3Cl