All calculatorsPercent Ionic Character Calculator
Estimate the % ionic character of a bond from electronegativity difference Δχ. Uses Pauling’s empirical relation and supports the Pauling (default) or Allred–Rochow scales. Enter elements or χ values directly, then see bond type, dipole direction, and an optional mini chart.
Background
A simple undergrad estimate relates Δχ to ionic character: \( \%\,\text{ionic} \approx \bigl(1 - e^{-0.25(\Delta\chi)^2}\bigr)\times 100 \). Threshold guide: Δχ < 0.4 (nonpolar), 0.4–1.7 (polar), > 1.7 (predominantly ionic).
Formula & Equation Used
Pauling relation (empirical): % ionic ≈ (1 − e−0.25(Δχ)2) × 100
Where: Δχ = |χ(A) − χ(B)| (electronegativity difference)
Bond guide: Δχ < 0.4 → nonpolar; 0.4–1.7 → polar; > 1.7 → ionic
Examples
Na–Cl:
χ(Na)=0.93, χ(Cl)=3.16 → Δχ=2.23 → % ionic ≈ 63% → ionic
C–H:
χ(C)=2.55, χ(H)=2.20 → Δχ=0.35 → % ionic ≈ 3% → nonpolar
H–F:
χ(H)=2.20, χ(F)=3.98 → Δχ=1.78 → % ionic ≈ 66% → polar covalent
Frequently Asked Questions
Q: How accurate is this % ionic?
It’s an empirical estimate for trends; real bonds depend on lattice energies and environment.
Q: Which electronegativity scale is used?
Pauling by default. Advanced mode adds Allred–Rochow, with fallback noted when unavailable.
