Clar Formulas: How to Draw and How not to Draw Formulas of Polycyclic Aromatic Hydrocarbons

Abstract

Historically, the aromatic sextet originates with Crocker (2), Armit and Robinson (3), and Hückel (4). The inscribed circle for denoting an aromatic sextet was introduced by Armit and Robinson, but it was Clar who defined how the sextet was to be used in polycyclic aromatic compounds. However, in some papers a mistaken form of Clar formulas is found. The present note stipulates that such mistakes should be corrected before their acceptance in respectable scientific journals, including this Journal.

Keywords:

• Clar structures
• polycyclic aromatic compounds