3.1.1: Resonance

• Resonance structures are two or more Lewis Structures that collectively describe the electronic bonding of a single polyatomic species including fractional bonds ands fractional charges.
• Resonance structures describe delocalized electrons that cannot be expressed by a single Lewis formula with an integral number of covalent bonds.
• The position of the atoms is the same in the various resonance structures, but the position of the electrons is different.
• Double-headed arrows link the different resonance structures of a compound and indicates that the actual electronic structure is an average of those shown.
• The net sum of valid resonance structures is defined as a resonance hybrid.
• A molecule that has several resonance structures is more stable than one with fewer.