Carbon tetrachloride (CCl4) is a nonpolar molecule even though all its bonds are polar, covalent bonds. This is because the polar bonds are arranged symmetrically around the central carbon atom, canceling out the individual polarities.
Carbon tetrachloride has a central carbon atom surrounded by four chlorine atoms in a tetrahedral shape. The four carbon-chlorine bonds are spaced symmetrically in 109.5 degree angles around the carbon atom. Chlorine is more electronegative than carbon. Therefore in each carbon-chlorine bond, the bonded electron pair draws closer to the chlorine atom, making each bond polar.
Despite having four polar bonds, the molecule itself is nonpolar because of its symmetry, which allows the bond polarities to cancel each other out, leaving the molecule with no net dipole moment.