Question

In terms of structure and/or distribution of charge, why is `CO_2` a nonpolar molecule?

Answer 1

Because the vector sum of the indvidual bond dipoles is ZERO.......

Explanation:

Polarity reults from the geometric sum of the individual bond dipoles. For the `""^(delta^+)C=O^(delta^-)` bond there is some polarity, some charge separation. However, this polarity is precisely balanced by geometric summation with the other `""^(delta^-)O=C^(delta^+)` dipole, on the other side of the molecule. And thus carbon dioxide is a non-polar molecule.

On the other hand, for the carbon monoxide molecule, `""^(-)C-=O^+`, there is necessairly some degree of molecular polarity.