# What causes dipole moment?

##### 1 Answer
Oct 25, 2015

the difference between electronegativity of bonds in the molecule

#### Explanation:

electronegativity is the affinity of an atom to attract electrons in a covalent bond.
electronegativity (if i take it as $E$) depends on the $\frac{e}{r}$ rario of the element. when the ratio is high, $E$ is high and vise versa.

when there is a difference of the $E$ values of atoms present in a covalent bond, a dipole moment occurs.

when the difference of the $E$ values rises, the dipole moment rises making the ionic nature of the bond to go higher. when the difference is usually higher than 1.8 or 2.0, we call it an ionic bond