An understanding of molecular dipoles provides insight into how molecules interact and helps to explain many of their properties.

A molecule possesses a dipole if it is electrically asymmetric, i.e. if the centers of the distributions of positive and negative charge within the molecule are different. When a molecule possesses a dipole, it is said to be polar. The dipole moment is equal to the magnitude of the equal and opposite charges multiplied by the distance between the centers of the charge distributions.

In a covalent bond between atoms with unequal electronegativities (i.e. having unequal attraction for electrons), the atom with the larger electronegativity will attract the electrons shared in the bonding molecular orbital more, and the shared electrons will spend more time near that atom. It will, consequently, have a partial negative charge. The less electronegative atom will have a partial positive charge since the...