Flexi Says: Resonance is the use of two or more Lewis structures to represent the covalent bonding in a molecule. One of the valid structures is referred to as a resonance structure. It is now understood that the true structure of a molecule that displays resonance is that of an average or a hybrid of all the resonance structures. In the case of the O3 molecule, each of the covalent bonds between O atoms is best thought of as being “one and a half” bonds, as opposed to either a pure single bond or a pure double bond. This “half-bond” can be shown as a dotted line in both the Lewis structure and the molecular model.
