How many pi bonds are in CO_2?

1 Answer
Dec 6, 2016

2 pi bonds

Let's consider the lewis structure of CO_2, and we can consult our molecular orbital manifold between the bonding species if need be.

Explanation:

For CO_2 we have:
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We know that sigma bonds form for single bonds (including dative bonds), and that the pi bonds will be all of the bonds which form thereafter.

Counting the bonds within the species, I see two pi bond, and two sigma bond.

Let's place the electron between the bonding oxygen and central atom carbon in our molecular orbital manifold:
enter image source here

Notice how the electron from both species, distributed into the manifold are colored red - can you count the number of pi bond that are present within the manifold? I see one pi bond within the manifold - and the manifold is done for exactly half of the symmetrical species. So, noting that the other half of the species will follow the same configuration - we can deduce that there are 2 pi bond in the CO_2 species.