1. The extent of ionic character in a covalent bond can be related to the electronegativity difference of the bonded atoms.
2. In a typical polar molecule Aδ- – Bδ+ the electronegativity difference (XA – XB ) can be used to predict the percentage of the ionic character as follows
3. If the electronegativity difference XA – XB is equal to 1.7, then the bond A – B has 50% ionic character.
4. If it is greater than 1.7, then the bond XA – XB has more than 50% ionic character.
5. If it is greater than 1.7, then the bond A – B has more than 50% ionic character.
6. If it is lesser than 1.7, then the bond A – B has less than 50% ionic character.