Question

Does $\mathrm{CO}$ have a double bond?

Answer 1

The double bond in $\mathrm{CO}$ is explained in following ways:

1. Carbon monoxide $\left(\mathrm{CO}\right)$ has two resonance structures.
2. The bond present in this molecule has two different configurations.
3. In the first configuration, between $\mathrm{C}$ and $\mathrm{O}$ exists a double bond, and the two atoms have zero formal charge.

Therefore, the above mentioned points clearly explain the formation of double bond in $\mathrm{CO}$.