Carbon dioxide (CO2) is classified as a nonpolar covalent molecule. This classification is due to its linear molecular geometry, which allows the dipole moments of the polar bonds to cancel each other out. In CO2, carbon is bonded to two oxygen atoms. The carbon-oxygen bonds are polar because oxygen is more electronegative than carbon, but the molecule’s symmetrical linear shape means that the overall dipole moment is zero.
When it comes to solvent compatibility, CO2 is more likely to dissolve better in nonpolar solvents. Between water and carbon tetrachloride (CCl4), carbon tetrachloride would be the better solvent for CO2. Water is a highly polar solvent, while carbon tetrachloride is nonpolar. According to the principle of ‘like dissolves like’, a nonpolar solute such as CO2 will be more soluble in a nonpolar solvent like carbon tetrachloride due to the similar intermolecular forces at play.