Question

Draw resonance structures for the following species:

Short answer

Here five resonating structures are possible.

Step-by-step solution

Step-by-Step Solution Step 1: Resonance

Resonance is a method to represent delocalized electrons within certain molecules or polyatomic ions when the bonding cannot be concluded by a single Lewis structure.

Resonance occurs when two double bonds are present consecutively or a double bond is followed by a single bond which is followed by another double bond, triple bond, positive charge, negative charge, or a free radical.

Rules for structures of resonance form

Rule 1

Individual resonance forms are imaginary which means they are not real. The real structure is a composite or resonance hybrid of all the different forms together.

Rule 2

Resonance forms differ only in the placement of their or nonbonding electrons. So, the position or the hybridization of an atom doesn’t change.

Rule 3

Different resonance forms of molecules don’t have to be equivalent. It can be converted into its anion by reaction with a strong base. The resultant anion can have resonance forms.

Rule 4

Resonance forms obey normal rules of valency. A resonance form like any other structure has to follow the octet rule.

Rule 5

The resonance hybrid is more stable than any individual resonance form. So, resonance leads to stability. More the number of resonance structures will be stable.

Structures of resonance forms

By using the above-mentioned rules we can draw the structure of the compound by delocalizing the double bond present in the molecule.

Resonating structures