Chemical Bonding and Molecular Structure

Chemistry · Class 11

Simulation · Chemistry · Class 11

Resonance: one real structure

From the lesson Resonance structures in Chemical Bonding and Molecular Structure. Change the values and watch what happens.

Resonance: one real structureChemistry · Class 11

The idea behind it

NCERT § "Resonance Structures"

  • If no one Lewis structure can describe a molecule, several structures are drawn that share the same arrangement of nuclei but place the electrons differently; the real molecule is a hybrid of them.
  • Ozone has two equal O–O bonds of 128 pm, between a single (148 pm) and a double (121 pm) O–O bond, which no single Lewis structure can show.
  • The carbonate ion has three identical C–O bonds, and CO₂ is also described by resonance.
  • The resonance hybrid has lower energy than any contributing structure, which stabilises the molecule.
  • Resonance structures do not exist separately and the molecule does not flip between them; there is no equilibrium between the canonical forms.