Institution: | Laboratoire de Chimie Théorique, Université de Nancy I, Case Officielle No. 140, 54037 Nancy, Cedex France Eidgenossische Technische Hochschule, 8006, Zurich, Universitatstrasse, 22 Suisse |
Abstract: | In order to complete the rs structure of chlorobenzene given in a preceding paper, a variety of isotopic species of this molecule were synthesized and their microwave spectra studied. This made twenty isotopic species available, enabling the determination of the geometrical parameters by a least squares method. Fitting only differences of moments of inertia either for monosubstituted species or to multiply substituted species gave the same result. They hardly differ from the ro values and agree with the rs values obtained by the Kraitchman equations. The resulting error limits were reduced, however. The following structural parameters were obtained, C1C2 = 1.399 Å, C2C3 = 1.386 Å, C3C4 = 1.3976 Å, C1Cl = 1.7248 Å, C2H2 = 1.080 Å, C3H3 = 1.081 Å, C4H4 = 1.081 Å, C6C1C2 = 120° 16, C1C2C3 = 119°78, C2C3C4 = 120°24, C3C4C5 = 119°80, C1C2H2 = 119°45, C2C3H3 = 119°76. The structure of the ring differs significantly from C6 symmetry. The deformation can be regarded as a compression of the position C1 while the angle of C2H2 bond is also changed. |