ChemBench

Electronegativity Difference Calculator

Predict a bond's character from two element symbols.

Element 1

Element 2

Electronegativity difference

2.23

Ionic

What you entered

Element 1: NaElement 2: Cl

1
Electronegativity of Na
Na= 0.93
2
Electronegativity of Cl
Cl= 3.16
3
Difference
|0.93 − 3.16|= 2.23

Result

Difference: 2.23

A difference of 2.23 between Na and Cl indicates a ionic bond.

Electronegativity difference and predicted bond type

Subtract the two Pauling electronegativities. The usual teaching cutoffs are below 0.4 nonpolar covalent, 0.4 to 1.7 polar covalent, and above 1.7 ionic.

Bond	Difference	Predicted type
C-C	0.00	Nonpolar covalent
H-H	0.00	Nonpolar covalent
C-H	0.35	Nonpolar covalent
C-O	0.89	Polar covalent
H-O	1.24	Polar covalent
H-F	1.78	Ionic
Mg-O	2.13	Ionic
Na-Cl	2.23	Ionic

H-F is the standard exception worth knowing: the 1.7 rule labels it ionic, but hydrogen fluoride is a molecular gas with a polar covalent bond. The cutoffs are a rough guide, not a law, and they work poorly whenever both atoms are non-metals.

Electronegativity difference predicts bond type

A difference under 0.5 typically means nonpolar covalent (electrons shared evenly), 0.5 to 1.7 means polar covalent (shared unevenly), and above 1.7 usually means ionic (electrons transferred rather than shared).

Why this ranking exists

These aren't hard boundaries — bond character exists on a continuum — but the electronegativity difference is the single most useful number for predicting whether a compound will behave more like table salt (ionic) or like water (polar covalent).

Frequently asked questions

The electronegativity difference between Na (0.93) and Cl (3.16) is 2.23 — what type of bond is that?

A difference of 2.23 is well above the 1.7 threshold, indicating an ionic bond. NaCl is indeed a classic ionic compound.

What is the cutoff between polar and nonpolar covalent?

Below 0.5 is generally nonpolar covalent (electrons shared evenly). Between 0.5 and 1.7 is polar covalent. Above 1.7 is ionic. These are guidelines, not absolute rules — the transition is gradual.

How is this related to the pH calculator?

Electronegativity affects how easily a molecule donates or accepts protons (H+ ions). Highly electronegative atoms stabilize negative charges, making some acids stronger — which directly influences pH. But this calculator predicts bond type, not acidity.