Interesting ChemistryEnergyEnergy LevelsHigher EnergyΠ-electron Resonance EnergyChemical SciencesLonger is stronger.https://doi.org/10.59350/tm2r5-cyh62Published June 6, 2009 in Henry Rzepa's BlogAuthor Henry RzepaExportCitationThe iconic diagram below represents a cornerstone of organic chemistry.