The title compound gives a single 35Cl and two 81Br NQR lines. The Zeeman effect on 35Cl and 81Br lines in a single crystal has been observed at room temperature. The locations of the principal z axes of the field gradient have been determined with an uncertainty of 0.05°. The angles between the C-X and C-Y bonds (X, Y=Cl or Br) are deduced on the basis of the orientations of the z axes. The angle between the C-Br bonds is 123.8° and the angles between the C-Cl and C-Br bonds are 116.5°and ll9.6°.