The carbonate ion CO3- has three resonance structures. In each resonance structure, the central carbon atom is double-bonded to one oxygen atom and single-bonded to the other two oxygen atoms. The double bond is distributed among the three oxygen atoms, with each oxygen atom having a double bond in one of the resonance structures. The negative charges are distributed among the two oxygen atoms with single bonds.Here are the three resonance structures:1. O=C-O - -O - 2. O - -C=O-O - 3. O - -O - -C=OIn these structures, the - represents a negative charge on the oxygen atom. The actual structure of the carbonate ion is a hybrid of these three resonance structures, with the double bond and negative charges distributed equally among the three oxygen atoms.