Explain the important aspects of resonance with reference to the `CO_(3)^(2-)` ion.

Explanation

When all the properrties of a molecule cannot be explained by a single structure, some probable hypotential structures (canonicall structures) are used. The actual structure is called the resonance hybrid which is an intermediat of the canonical structures. this is termed as resonance. Carbonate ion `(CO_(3)^(2-))` can be represented by a combination of the following 3 resonating structures in which `CO_(3)^(2-)` is the resonance hybrid of the three canonical structures II and III.

If `CO_(3)^(2-)` ion could be represented by only one structure, there would be two C-O single bonds and one C=O double bond. however, experimental results have shown that the length of all the carbon-oxygen bonds are equal. due to resonance, all the carbon-oxygen bonds are equivalent and possess partial double bond character. in each canonical form, the position of the atoms is identical whereas the distribution of electrons is different. also , the number of paired electrons in each structure is the same. the atoms participating in resonance lie in the same plane and each structure is a perrfect lewis structure. the energy and stability of each canonical structure is also same. thus, `CO_(3)^(2-)` is actually the resonance hybrid (IV) of the canonical structures I, II and III.