The nitrate ion NO3- has three resonance structures. In each resonance structure, the nitrogen atom is at the center and is bonded to three oxygen atoms. The nitrogen atom has a positive charge, and one of the oxygen atoms has a negative charge. The other two oxygen atoms have double bonds with the nitrogen atom. The resonance structures can be represented as follows:1. O=N-O - -O2. O - -N=O-O3. O-O - -N=OIn these structures, the single and double bonds between the nitrogen and oxygen atoms are constantly shifting, causing the electrons to be delocalized among the oxygen atoms. This delocalization of electrons results in the formation of partial double bonds between the nitrogen and each oxygen atom, making the nitrate ion more stable. The actual structure of the nitrate ion is a hybrid of these three resonance structures, with each oxygen atom having a partial double bond with the nitrogen atom.