Which electronegativity scale is most common?

The Pauling scale is the most widely used. Fluorine has the highest value at 3.98, and cesium/francium have the lowest around 0.7.

Are the cutoff values exact?

No, the 0.4 and 1.7 boundaries are guidelines, not rigid rules. Some textbooks use slightly different values. Bond character is actually a spectrum from pure covalent to pure ionic.

Can a bond be 100% ionic?

In practice, no bond between different atoms is perfectly 100% ionic. Even NaCl has some covalent character. The classification is a useful simplification.

Calculadora de Diferencia de Electronegatividad

Determina el tipo de enlace (iónico, covalente polar o covalente no polar) a partir de los valores de electronegatividad.

Determina el tipo de enlace (iónico, covalente polar o covalente no polar) a partir de los valores de electronegatividad.

Electronegatividad del átomo 1

Electronegatividad del átomo 2

Formula

Delta EN = |EN1 - EN2|

What is This Tool?

Electronegativity measures an atom's ability to attract shared electrons in a chemical bond. The difference in electronegativity between two bonded atoms determines the bond type: nonpolar covalent, polar covalent, or ionic.

Formula

Delta EN = |EN(atom 1) - EN(atom 2)|

Bond type classification:
  < 0.4 : Nonpolar covalent
  0.4 - 1.7 : Polar covalent
  > 1.7 : Ionic

Worked Examples

1. O-H bond in water

Given: EN(O) = 3.44, EN(H) = 2.20

Delta EN = |3.44 - 2.20| = 1.24

1.24 is between 0.4 and 1.7

Result: Polar covalent bond

2. Na-Cl bond

Given: EN(Na) = 0.93, EN(Cl) = 3.16

Delta EN = |0.93 - 3.16| = 2.23

2.23 > 1.7

Result: Ionic bond

3. C-H bond in methane

Given: EN(C) = 2.55, EN(H) = 2.20

Delta EN = |2.55 - 2.20| = 0.35

0.35 < 0.4

Result: Nonpolar covalent bond

Frequently Asked Questions