Why is #CO_2# a nonpolar molecule, whereas #CO# is a polar molecule?

1 Answer
anor277
Jan 23, 2017

Consider the vector sum of the individual bond dipoles........

Explanation:

The #C-O# bond in both gases is polar to a certain, limited extent. #""^(+delta)C-=O^(delta-)# has some polarity; on the other hand, for #""^(delta-)O=^(delta+)C=O^(delta-)#, the vectors of the bond dipoles clearly sum to ZERO.

This polarity is not reflected in the boiling points of the 2 gases, #-191.5^@# for #CO# at #1*atm#, versus a normal sublimation point of #-78^@C# for carbon dioxide, however, carbon dioxide is a bigger molecule, with extra dispersion forces.

Related questions
See all questions in Polarity of Molecules
Impact of this question
5449 views around the world
You can reuse this answer
Creative Commons License