Why when a chemical species is stablized by resonance, its energy

[abcd8989]

Why when a chemical species is stablized by resonance, its energy level is lower? As I know, resonance is only a kind of electrons delocalization within the species. There is no interaction between that species and the environment.

 

[zhermes]

Stabilization is equivalent to lowering the energy. Conceptually, you can think of the charge being more evenly distributed when the electrons are delocalized---thus decreasing the electrostatic repulsion between like-charges, and better saturating between opposite charges (i.e. nuclei and electrons).
These processes don't require any interaction with the environment.