Nuclear quadrupole coupling constants of halogenated hydrocarbons and their relation to the natural hybrid orbitals

The natural hybrid orbitals of halogen atoms in various halogen‐substituted alkanes and benzenes have been calculated by the Fenske–Hall MO SCF method and natural hybrid orbital theory. Four consistent parameters i, s, d and π are derived to describe the nuclear quadrupole coupling constant (QCC) of the halogen isotopes ³⁵Cl, ⁸¹Br and ¹²⁷I, with modification by the asymmetry parameter η. A semi‐empirical expression is proposed from a different point of view.