Friedl oscillations and charge alteration in long, conjugated organic molecules are representations of the same phenomenon. A similar can be observed in low-weight organic compounds such as α,β-unsaturated carbonyl, and it has a profound impact on their reactivity. These species represent a typical case of a conjugated carbon system perturbed by a heteroatom -oxygen in this case. In terms of FOs, heteroatoms act as impurities that perturb the electronic state of the molecule.