Calculadora de Nome Químico (Composto Iônico)
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
índice_cátion = |q_ânion| ; índice_ânion = q_cátion
About this calculator
This chemical name calculator for ionic compounds helps you determine the correct chemical formula from the name or vice versa by performing charge balance between cations and anions. It is useful for chemistry students, teachers, and professionals who need to quickly verify the stoichiometry of ionic compounds.
The operation is simple: enter the cation (positive ion) and its charge, and the anion (negative ion) and its charge. The calculator applies the charge balance rule: the subscript of the cation equals the absolute value of the anion's charge, and the subscript of the anion equals the cation's charge. The result is the balanced chemical formula, such as NaCl, MgO, or Al2O3.
Use this calculator when you need to write formulas of ionic compounds, such as oxides, hydroxides, salts, or acids (considering ions). It is especially useful in general chemistry exercises, exam preparation, or grading academic work. It avoids common subscript errors and ensures electrical neutrality of the compound.
Important precautions: verify that the ion charges are correct (consult the periodic table or oxidation rules). Remember that some metals can have multiple charges (e.g., Fe2+ and Fe3+). The calculator does not automatically simplify subscripts (e.g., Ca2+ and O2- results in Ca2O2, but the correct is CaO; simplify manually if needed).
Frequently asked questions
How does the calculator determine the subscripts of ions?
It uses charge balance: the subscript of the cation equals the absolute value of the anion's charge, and the subscript of the anion equals the cation's charge.
Do I need to simplify the subscripts after the result?
Yes, the calculator does not automatically simplify. For example, Ca2+ and O2- gives Ca2O2, but the correct is CaO. You should divide the subscripts by the greatest common divisor.
Does it work for polyatomic ions?
Yes, as long as you enter the correct charge of the polyatomic ion (e.g., SO4 2-). The charge balance is the same.
Can I use it for transition metal compounds?
Yes, but you need to know the specific charge of the metal (e.g., Fe3+). The calculator does not determine the charge; you must provide it.
What if the compound is covalent?
This calculator is only for ionic compounds. Covalent compounds use different naming rules (prefixes).