Concerning the Structure of [18]Annulene

A recent computational study of Schleyer and co‐workers [1] is reviewed, which led these authors to the firm conclusion that [18]annulene has a localized structure with alternating single and double C,C bonds, contrary to earlier crystallographic analyses of X‐ray‐diffraction data favoring a delocalized non‐alternating form. It is pointed out i) that deceptive orientational disorder phenomena in the crystal might be subject to experimental resolution in this case, and ii) that, in contrast to gas and solution phases, [18]annulene might possibly assume the non‐alternating structure in the crystalline solid state.