Explain why `CO_(3)^(2-)` ion cannot be represented by a single Lewis structure. How can it be best represented?

Explanation

A single Lewis structure of `CO_(3)^(2-)` ion cannot explain all the properties of this ion. It can be represented as a resonance hybrid of the following structures.

If, it were represented only by one structure, there should be two types of bonds i.e. C=O double bond and C-O single bonds but actually all bonds are found to be identical with same bond length and same bond strength.