Electronegativity Difference Calculator

Conventionally above 1.7, with 0.5 to 1.7 called polar covalent and below 0.5 nonpolar. These are teaching thresholds, not physical transitions — a bond at exactly 1.7 is about 51% ionic on Pauling's relation.

Pauling's empirical relation: 1 − exp(−Δ²/4), expressed as a percentage. It gives about 43% for the H–F bond and about 70% for Na–Cl.

The more electronegative one, because it pulls the shared electrons closer. In H–Cl the chlorine is δ− and the hydrogen δ+.

No. Even caesium fluoride, the largest electronegativity difference between stable elements at 3.19, works out around 92% ionic. Some electron sharing always remains.

Yes, when symmetry cancels the bond dipoles. Carbon dioxide has two strongly polar C=O bonds pointing in opposite directions, giving zero net dipole.

The Pauling scale, running from caesium at 0.79 to fluorine at 3.98. Mulliken and Allred–Rochow scales give different values, so mixing scales in one comparison produces meaningless differences.

From bond dissociation energies. Pauling observed that a bond between different atoms is stronger than the average of the two homonuclear bonds, and attributed the excess to ionic character. The scale is anchored by assigning fluorine 3.98.

Mulliken averages ionisation energy and electron affinity, giving a value with physical units. Allred–Rochow uses the electrostatic force on a valence electron. Both correlate well with Pauling and give different numbers, so mixing scales in one comparison is meaningless.

It rises left to right as nuclear charge increases with no new shell, and falls down a group as the valence shell moves further from the nucleus. Fluorine at 3.98 is the maximum and caesium at 0.79 the minimum among stable elements.

Only the ones that form compounds. Xenon is given about 2.6 and krypton about 3.0. Helium, neon and argon form no stable compounds, so there is no bond to measure and no value assigned.

Debyes. Water is 1.85 D, ammonia 1.47, hydrogen chloride 1.08, and carbon dioxide 0 by symmetry. One debye is about 3.336 × 10⁻³⁰ coulomb metres — a unit that survives because the SI equivalent is unwieldy at molecular scale.

Indirectly, through polarity. Like dissolves like: polar solvents dissolve polar and ionic solutes, nonpolar solvents dissolve nonpolar ones. But molecular geometry decides overall polarity, so bond-level differences alone are not enough to predict it.