Calculadora de Caráter Iônico
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
% iônico = (1 − e^(−0.25·Δχ²)) × 100
About this calculator
The Ionic Character Calculator determines the percentage of ionic character in a chemical bond between two elements, based on the electronegativity difference according to the Pauling scale. Ionic character indicates how close the bond is to a purely ionic bond, as opposed to covalent. The greater the electronegativity difference, the higher the tendency for electron transfer and, consequently, the higher the ionic character.
The calculation uses the formula % ionic = (1 − e^(−0.25·Δχ²)) × 100, where Δχ is the electronegativity difference between atoms. This empirical equation, proposed by Pauling, models the gradual transition between covalent and ionic bonds. Δχ values near zero result in low ionic character (pure covalent bond), while differences above 1.7 typically indicate ionic character greater than 50%.
Use this calculator to classify bonds in chemical compounds, predict properties such as solubility and melting point, or in educational contexts of general chemistry. For example, comparing NaCl (Δχ ≈ 2.1) and HCl (Δχ ≈ 0.9), the tool shows that NaCl has a much higher ionic character, consistent with its salt behavior. Remember that the model is an approximation and does not consider effects of polarizability or molecular geometry.
Cautions: the Pauling formula is empirical and does not apply to metallic bonds or compounds with significant covalent character due to d or f orbitals. Also, electronegativity varies by scale (Pauling, Mulliken, Allred-Rochow). Ensure consistent values. For bonds with Δχ > 2.0, ionic character exceeds 90%, but in practice many bonds are considered ionic only above 50%.
Frequently asked questions
What does 50% ionic character mean?
It indicates the bond is half ionic and half covalent. In practice, bonds with ionic character above 50% are often considered predominantly ionic.
Can I use the calculator for metallic bonds?
No, the Pauling formula was developed for bonds between nonmetals or between a metal and a nonmetal. Metallic bonds involve delocalized electrons and are not well described by this model.
What electronegativity difference makes a bond ionic?
There is no exact value, but generally Δχ > 1.7 is used as an empirical threshold. Above that, ionic character exceeds 50%.
How do I get electronegativity values?
You can consult periodic tables that include the Pauling scale. Many general chemistry textbooks provide these values. The calculator expects you to input the difference directly.
Does the formula work for all elements?
It works best for s-block and p-block elements. For transition elements, ionic character may be overestimated due to shielding effects and d orbitals.