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Clar's sextet (cyan‐colored benzenoid ring) depictions of 4‐PA, 5‐PA and 7‐PA, and the calculated (CASSCF (8,8)/6‐31G**) diradical (y 0) and tetraradical (y 1) indices. The substituents in 4‐PA and 7‐PA are omitted in the resonance structures for clarity.
