Chemical Name Calculator (inorganic formula → IUPAC name: salts, acids, binary compounds)

Understanding the chemical name finder — concept and principle

This tool reads a simple inorganic formula and gives its systematic name following IUPAC rules: salts with Stock numbers for variable-charge metals, binary molecular compounds with Greek prefixes, common oxoacids and hydrates.

How it is calculated

• Salts: cation first, then anion. Monatomic anions end in -ide (chloride, oxide); oxoanions keep their names (sulfate, nitrate, hydroxide).
• Variable-charge metals (Fe, Cu, Sn, Pb, Mn …): the metal's charge is worked out from the anion so the formula is neutral and written as a Roman numeral.
• Binary molecular compounds of two nonmetals use Greek prefixes (mono-, di-, tri- …), dropping mono- on the first element.
• Acids of hydrogen with an oxoanion take acid names (H₂SO₄ = sulfuric acid). Hydrates add "-hydrate".

The principle

Systematic names encode the composition so that a name leads back to one formula. For ionic compounds, charges must balance; that is how the metal's oxidation state can be deduced from the anions. For molecular compounds, which have no ions to balance, prefixes state the numbers of atoms directly. The rules come from IUPAC's Nomenclature of Inorganic Chemistry ("Red Book", 2005).

Worked example

Default input: Fe2(SO4)3.

1. Anion: sulfate, SO₄²⁻; three of them carry 3 × (−2) = −6.
2. Two iron ions must balance +6, so each is Fe³⁺.
3. Type of compound: ionic (metal + anion); ratio 2 : 3.
4. Name = iron(III) sulfate; no water of crystallisation (—).

How to read the result

The Roman numeral is essential: iron(II) sulfate (FeSO₄) and iron(III) sulfate are different substances with different properties. Older names such as ferric sulfate are still seen on labels; the Stock name avoids ambiguity.

Common mistakes

• Using prefixes for ionic compounds ("diiron trisulfate" is not the standard name).
• Forgetting the Roman numeral for metals with more than one common charge.
• Confusing sulfate (SO₄²⁻) with sulfite (SO₃²⁻).
• Writing formulas in an unusual order that the tool cannot parse.

Frequently asked questions

What is the name of Fe2(SO4)3?

Iron(III) sulfate, also called ferric sulfate.

When do you use Roman numerals in chemical names?

For metals that can form ions of different charges, such as iron, copper, tin and lead.

When are Greek prefixes used?

For binary compounds of two nonmetals, such as N₂O₅, dinitrogen pentaoxide.

Sources: IUPAC (2005). Nomenclature of Inorganic Chemistry: IUPAC Recommendations 2005 ("Red Book"). RSC Publishing · 대한화학회, 무기화합물 명명법