Question

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

Answer 1

Lewis structure does not explain all the properties of the molecule. As a result, it is possible to draw a number of structures to explain all the features.

These structures are called “resonating structures” and resonance which means that a molecule can be expressed in different forms and none of which can explain all the properties of the molecule.

As in case of ion all the $C{ O }_{ 3 }^{ 2- }$ bonds are equivalent.

Therefore, it is not correct to representation $C{ O }_{ 3 }^{ 2- }$ ion through one Lewis structure.

Instead three resonating structures can be drawn which are as follows:

Answer 2

Answer:

According to experimental findings, all carbon to oxygen bonds in CO32- are equivalent.

Hence, it is inadequate to represent CO32- ion by a single Lewis structure having two single bonds and one double bond.

Therefore, carbonate ion is described as a resonance hybrid of the following structures:

Resonating structure of CO3-2