Question

What is the hybridization in `"CO"_2`?

Answer 1

The carbon atom has `sp` hybridization; the `"O"` atoms have `sp^2` hybridization.

Explanation:

You must first draw the Lewis structure for `"CO"_2`.

According to VSEPR theory, we can use the steric number `("SN")` to determine the hybridization of an atom.

`"SN"` = number of lone pairs + number of atoms directly attached to the atom.

• `"SN = 2"` corresponds to `sp` hybridization.
• `"SN"= 3"` corresponds to `sp^2` hybridization.

We see that the `"C"` atom has `"SN = 2"`. It has no lone pairs, but it is attached to two other atoms.

It has `sp`hybridization.

Each `"O"` atom has `"SN = 3"`. It has 2 lone pairs and is attached to 1 `"C"` atom.

Just as the carbon atom hybridized to form the best bonds, so do the oxygen atoms.

The valence electron configuration of `"O"` is `["He"] 2s^2 2p^4`.

To accommodate the two lone pairs and the bonding pair, it will also form three equivalent `sp^2` hybrid orbitals.

Two of the `sp^2` orbitals contain lone pairs, while the remaining `sp^2` orbital and the unhybridized `p` orbital have one electron each.

We can see this arrangement in the `"C=O"` bond of formaldehyde, which is equivalent to the right-hand side of the `"O=C=O"` molecule.

(from www.slideshare.net)

There is a similar arrangement on the left side of the `"O=C=O"` molecule, but the `pi` bond is horizontal rather than vertical.

Here is a video about the hybridization of carbon dioxide.