Whenever a single Lewis structure cannot describe a molecule accurately, a number of structures with almost similar energy, position of nuclei, bonding and non-bonding pairs of electrons are taken as the canonical structures of the hybrid which describes the molecule accurately. This concept is known as

According to the concept of resonance, whenever a single Lewis structures cannot describe a molecule accurately, a number of structures with similar energy, position of nuclei, bonding and non-bonding pairs of electrons are taken as the canonical forms of the hybrid which describe the molecule accurately.