THE MOLECULAR-STRUCTURE OF CHLOROBENZENE, DETERMINED BY THE COMBINED ANALYSIS OF ELECTRON-DIFFRACTION, ROTATION CONSTANT AND LIQUID-CRYSTAL NUCLEAR-MAGNETIC-RESONANCE DATA

The molecular structure of chlorobenzene has been determined from new electron diffraction data and existing microwave data in the gas phase and direct dipolar couplings between spin- 1 2 nuclei in the NMR spectrum of a sample dissolved in a nematic liquid crystal solvent. The data, when corrected to a common basis (r0α), are compatible with a single structure in which the ring geometry is distorted by the chlorine substituent so that CC bonds adjacent to Cl are shorter than the others, and the CCC bond angle at the substituted carbon atom is larger than 120°. The refined structural parameters are rC(1)C(2) 139.08(18), rC(2)C(3) 139.42(16), rC(3)C(4) 140.00(12), rCCl 173.90(23), rC(2)H 107.79(21), rC(3)H 108.72(21), rC(4)H 107.95(21) pm; ∠C(6)C(1)C(2) 121.65(23), ∠C(1)C(2)C(3) 119.05(15), ∠C(2)C(3)C(4) 120.24(12), ∠C(3)C(4)C(5) 119.79(11), ∠C(1)C(2)H 119.67(25), ∠C(2)C(3)H 120.41(19) degrees. © 1990.