Figure 4.

Plot of the energy and the H—C—C—Cl dihedral angle vs. position along the reaction coordinate at HF/6–31+G(d) level of theory for Reaction 5. The dihedral angle does not change until the reaction has almost reached a stationary point. (Insets) Shown are the HF/6–31+G(d) calculated structures for the reaction of chloroethane with hydroxide (Reaction 5) at reaction coordinate unit 9.0 and unit 15.4.