* Electronegativity: Oxygen is more electronegative than carbon. This means oxygen has a stronger pull on the shared electrons in the bond.

* Unequal Sharing: The shared electrons spend more time closer to the oxygen atom, creating a partial negative charge (δ-) on the oxygen and a partial positive charge (δ+) on the carbon.

* Dipole Moment: This uneven distribution of charge results in a dipole moment, a measure of the molecule's polarity.

While the CO bond is strong, the difference in electronegativity between carbon and oxygen leads to a polar covalent bond and a polar molecule overall.