Covalent bond

Covalent bonds are always formed when the valence electrons of the bonding partners are shared to attain the equivalent of a joint, completely full outer electron shell (noble gas shell). If the electronegativity of the bonding partners is different, the centre of charge in the compound shifts so that a dipole is formed with a negative centre in the region of the more electronegative partner, and a positive centre in the region of the less electronegative bonding partner.