Chemical Nomenclature Calculator
Convert a chemical formula to its systematic name and back, for acids, bases, salts, oxides and other common compounds.
What this calculator does
Choose a direction, type a formula or a name, and get the other one for more than 150 common inorganic and organic substances.
When you need it
Naming compounds correctly is needed to read lab procedures, safety data sheets and textbooks, and it is a standard topic in the first weeks of general chemistry.
Formulas
- Ionic compound: name of the cation + name of the anion (with a Roman numeral for metals with variable charge)
- Binary acid: hydro- + root + -ic acid; oxyacid: root + -ic or -ous acid
How to use it
- Pick formula to name or name to formula.
- Type the formula, for example Fe2O3, or the name.
- Read the result.
Worked example
Name Fe2O3.
- Oxygen is O²⁻, and there are 3 of them: total charge −6
- Two iron ions must carry +6, so each is Fe³⁺
- Name the cation with its charge, then the anion: iron(III) oxide
Answer
Fe2O3 is iron(III) oxide.
Common mistakes
- Leaving out the Roman numeral for transition metals.
- Writing the anion first.
- Mixing up -ate and -ite endings for oxyanions.
Related tools
Frequently asked questions
How do you name an ionic compound?
Name the cation first, then the anion with an -ide ending (for single atoms). Use a Roman numeral when the metal can have more than one charge.
What is the formula of sulfuric acid?
H2SO4.
What is the difference between -ate and -ite?
The -ate ion has one more oxygen than the -ite ion, for example sulfate SO4²⁻ and sulfite SO3²⁻.