Molecular Structure of Ethyl Chloride

Abstract

The microwave spectra of C¹³H₃CH₂Cl³⁵, CH₃C¹³H₂Cl³⁵, CH₃CD₂Cl³⁵, and CH₂DCH₂Cl³⁵ have been examined and rotational constants assigned. Both a‐type and b‐type spectra have been observed. From these spectra and those previously reported for CH₃CH₂Cl³⁵, CH₃CH₂Cl³⁷, and CH₂DCH₂Cl³⁵ a complete structure has been obtained by means of the substitution method. The bond distances and bond angles obtained are as follows: CC = 1.520 A, CCl = 1.788 A, CH (methyl) = 1.091 A, CH (methylene) = 1.089 A, CCCl = 111°2′, HCH (methyl) = 108°30′, HCH (methylene) = 109°12′, CCH (methylene) = 111°36′. The quadrupole coupling parameters and barrier to internal rotation have been re‐evaluated in terms of the above structure. The quadrupole coupling parameters are χ_bond = —68.80 Mc and η_bond = 0.035, if the angle between the a axis and the CCl bond is determined from the structure; or χ_bond = —71.24 Mc, if a cylindrical charge distribution is assumed near the chlorine nucleus. The barrier to internal rotation is 3685 cal/mole.