Two C=O double bonds; two lone pairs on each oxygen
Total valence electrons16
Central atomCarbon
Molecular geometryLinear
Bond angle180°
CO2 Lewis structure overview
Carbon contributes four valence electrons and the two oxygen atoms contribute twelve, for sixteen total. A skeleton with carbon in the center is required because oxygen is normally terminal. Starting with two single bonds leaves carbon short of an octet. Converting one lone pair from each oxygen into a bonding pair creates two double bonds.
How to draw the CO2 Lewis structure
Count 16 valence electrons.
Add 4 from carbon and 6 from each oxygen.
Place carbon in the center.
Use the skeleton O–C–O.
Draw single bonds and complete oxygen octets.
After placing lone pairs on oxygen, carbon has only four electrons around it.
Form two double bonds.
Move one lone pair from each oxygen into a C–O bond to make O=C=O.
Verify formal charges.
The two-double-bond structure gives formal charge zero on carbon and both oxygens.
Formal charges
Carbon owns half of eight bonding electrons, equal to its four valence electrons. Each oxygen owns four nonbonding electrons plus half of four bonding electrons, equal to six. Every formal charge is zero.
Geometry and polarity
Carbon has two electron domains, so VSEPR predicts a linear molecule. Each C=O bond is polar, but the equal dipoles point in opposite directions and cancel; CO2 is nonpolar overall.
Common mistakes
Stopping at O–C–O with single bonds, which leaves carbon without an octet and creates large formal charges.
Putting carbon at an end of the structure.
Adding lone pairs to carbon in the final lowest-charge structure.
Calling the molecule bent because oxygen has lone pairs; geometry is determined around the central carbon.
Frequently asked questions
Does carbon have lone pairs in CO2?
No. In the standard O=C=O Lewis structure, carbon has two double bonds and no lone pairs.
Why is CO2 linear?
The central carbon has two electron domains. They arrange 180° apart to minimize repulsion.
Is CO2 polar?
The bonds are polar, but the linear symmetry makes their dipoles cancel, so the molecule is nonpolar.