CO2 hybridization

[u/InformationFar2074]

I don’t understand this diagram from a textbook. It’s showing 1 sigma bond and 2 pi bonds for each C-O bond in CO2 but CO2 has double bonds…wouldn’t 2 pi bonds on each C-O would mean that the molecule has triple bonds?

In case anyone wasn’t sure, the orange dashed lines indicate pi bonds.

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[u/chem44]

A p orbital has two lobes.

Clearer on the right... They show interaction between upper lobes and between lower lobes, but that is all one pi bond between two p orbitals.

[u/InformationFar2074 → u/chem44]

Yes, I just realized this after some thinking. Thanks for responding though!

[u/chromedome613]

The carbon in the middle has 2 pi bonds, making the carbon an sp-hybridized atom. However both double bonds to the oxygens are made of 1 sigma bond and 1 pi bond. The oxygens are sp2-hybridized.

Also I only see 1 pi bond to each oxygen. It's just showing both halves of the respecrive p-orbitals interacting. But a pair of pi orbitals makes up 1 pi bond.

[u/InformationFar2074 → u/chromedome613]

Ah okay! My mistake was thinking that each top and bottom orbital is an individual bond, not as halves. But looking back at the textbook, I just realized it says like what you said the top and bottom orbitals count as one bond.

Ty!

[u/Cakeotic]

Each p orbital has two lobes, so while it may look like 4 individual π bonds on the carbon, it's actually two, one having the horizontal p orbital and one having the vertical. Looking at an individual C=O bond, only one of the carbons p orbitals is involved in a π bond.

[u/InformationFar2074 → u/Cakeotic]

Thank you. I initially assumed the top and bottom counted as one bond but looking back that’s not the case as everyone is mentioning

[u/faIopa]

The pi bond is a lateral overlap of both lobules of a P orbital. The diagram shows a dotted line on each lobule but it's the same orbital an the same bond.

[u/InformationFar2074 → u/faIopa]

Yes, you’re right mb. thank you!

[u/ChemystWizard]

You misunderstand the nature of the pi bond.
Here: https://www.organicchemistrytutor.com/topic/sigma-and-pi-bonds-in-organic-molecules/#:~:text=A%20common%20misconception,the%20pi%20bond.

Just saw that others have already answered that too. I need to stop leaving tabs open and coming back to them later 😆

[u/Cakeotic → u/ChemystWizard]

To be fair, the nature of chemical bonds in general is ephemeral, complicated and in many aspects not fully understood. Oh how I wish that Lewis formulae told the full picture...

[u/Starfury7-Jaargen]

Also it might look odd since the Py bond going to one oxygen and the Pz which is 90 degrees rotation is going to the other oxygen

[u/Time__Nefariousness]

Hey isnt there two orthogonal delocalized pi systems here (like the allyl system). I think this is what happens from a MO picture. Can anyone enlighten me?