Explain the important aspects of resonance with reference to the $CO_{3}^{2-}$ ion.

(N/A) Resonance is a phenomenon where a single Lewis structure cannot adequately describe the properties of a molecule or ion. In such cases, multiple canonical structures are written to represent the electronic distribution.
For the carbonate ion $(CO_{3}^{2-})$, the central carbon atom is bonded to three oxygen atoms. According to the Lewis structure, there is one double bond and two single bonds.
However, experimental evidence shows that all three $C-O$ bond lengths in the $CO_{3}^{2-}$ ion are identical $(127 \ pm)$, which is intermediate between the length of a $C-O$ single bond $(143 \ pm)$ and a $C=O$ double bond $(121 \ pm)$.
This indicates that the actual structure is a resonance hybrid of three canonical forms ($I$, $II$, and $III$), where the double bond is delocalized over all three $C-O$ bonds, as shown in the resonance hybrid structure $(IV)$.