Mills—Nixon Effect: Wherefore Art Thou?

Significant alternation of the bond lengths in benzene should be induced by small annelated rings—this is the basic tenet of the Mills–Nixon hypothesis formulated in 1930. Although the hypothesis was soon contested by Pauling et al., it has persisted doggedly ever since. Recent results from Vollhardt et al. revealed that the Mills–Nixon effect cannot be proved even in very highly strained systems such as 1–4.