Which type of bonds in a molecule contributes to creating a permanent dipole?

Polar covalent bonds contribute to creating a permanent dipole in a molecule because they involve the unequal sharing of electrons between atoms with different electronegativities. This disparity causes one end of the molecule to become partially negative, while the opposite end becomes partially positive, resulting in a dipole moment.

In a polar covalent bond, one atom pulls the shared electrons closer to itself, creating a charge separation within the molecule. This is in contrast to non-polar covalent bonds, where electrons are shared equally, and no charge separation occurs, resulting in no permanent dipole.

Ionic bonds can indeed create dipoles, but this happens within the context of the ionic charges of the constituent ions themselves rather than a permanent dipole in a molecular sense. Metallic bonds involve a sea of delocalized electrons and do not create permanent dipoles in the same way that polar covalent bonds do. Therefore, the nature of polar covalent bonds is what specifically leads to the formation of a permanent dipole in a molecule.