How this calculator works
The Pauling estimate maps an electronegativity difference to an empirical ionic fraction. The dipole method instead compares a measured bond moment with q times bond length for completely separated charges. These are distinct models and need not agree. Use a single bond moment rather than an entire polyatomic molecule moment. One debye equals 1e-21 divided by the exact speed of light in C m. One angstrom equals 1e-10 m.
Formula
Ionic fraction = 1 - exp(-difference squared / 4). Dipole fraction = measured moment / (q r), with consistent units.
Worked example
A Pauling difference of 2 gives fraction 1 - exp(-1) = 63.2121%. Equal electronegativities give 0%. A fully separated elementary charge at 1 angstrom gives about 4.8032 D.
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Frequently asked questions
Are both estimates exact?
No. The Pauling expression is empirical and the dipole ratio uses an ideal separated-charge model.
Can 100% give a finite Pauling difference?
No. That inverse tends to infinity, so the inverse mode requires a value below 100%.
Why does a zero molecular moment not prove covalent bonds?
Oppositely directed bond dipoles can cancel in a symmetric molecule.