A pair of separated opposite electric charges.
The dipole moment is the product of the positive charge
and distance between the charges.
are often state in debyes; the SI unit is the coulomb
In a diatomic molecule, such as HCI, the
dipole moment is a measure of the polar nature of
the bond i.e. the extent to which the average electron
charge is displaced towards one atom.
In a polyatomic
molecule, the dipole moment is the vector sum of the
dipole moments of the individual bonds.
In a symmetrical
molecule, such as tetrachloromethane (CCI4), there
is no overall dipole moment, although the individual
C-CI bonds are polar.