Chemical Name Calculator
Need a fast way to turn ions into a correct compound name or formula? The Chemical Name Calculator lets you select a cation and an anion then it instantly returns the balanced formula and the proper name that follows modern nomenclature rules. It saves time in homework, lab prep, or quick QA checks.
How to use the Chemical Name Calculator
You can work in two quick modes. Pick what you know then let the calculator finish the job.
Mode A — Search by formula
- Open the Cation symbol list then choose the positive ion. Examples: Na⁺, Fe³⁺, NH₄⁺.
- Open the Anion symbol list then choose the negative ion. Examples: Cl⁻, O²⁻, SO₄²⁻.
- Read the ionic compound name and the balanced formula. The tool adds subscripts and parentheses automatically.
Mode B — Search by name
- Select the Cation name. You’ll see Stock notation for variable-charge metals like Iron(II) or Iron(III).
- Select the Anion name such as Chloride, Nitrate, or Phosphate.
- Get the balanced formula in one click. You also see the compound name for confirmation.
Try a quick one. Choose Fe³⁺ and O²⁻. The calculator returns Iron(III) oxide and the formula Fe₂O₃. No scratch paper needed.
What the calculator does under the hood
Behind the scenes the logic stays simple yet rigorous. Ionic compounds must be electrically neutral. The total positive charge equals the total negative charge.
1) Charge balancing with the least common multiple
- Let the cation charge be +m and the anion charge be −n.
- The smallest whole-number ratio that neutralizes charge uses LCM(m, n).
- Counts become: cation subscript = LCM/m, anion subscript = LCM/n.
| Ion | Charge | LCM step | Subscript |
|---|---|---|---|
| Fe³⁺ | +3 | LCM(3,2)=6 | 6/3 = 2 |
| O²⁻ | −2 | LCM(3,2)=6 | 6/2 = 1 |
2) Parentheses for polyatomic ions
- Polyatomic ions behave as units. When you need two or more copies you must use parentheses.
- Example: Ammonium sulfate uses two ammonium ions to balance sulfate. You get (NH₄)₂SO₄.
3) Stock notation for multivalent metals
- Many transition metals form more than one stable cation. Names need a Roman numeral to show the oxidation state.
- FeCl₂ is Iron(II) chloride while FeCl₃ is Iron(III) chloride.
These rules align with modern guidance from IUPAC’s Gold Book and instructional summaries from the American Chemical Society.
Essential ionic naming rules you should know
You learn faster when you see patterns. Keep the following rules close by when you practice.
Rule 1 — Cation name first
Always say and write the metal or positive ion first. Then say the anion.
Rule 2 — “-ide” for monatomic anions
Single-element anions end in -ide. Chloride, oxide, nitride, and sulfide are common examples.
Rule 3 — “-ate” and “-ite” for oxyanions
Oxyanions use a family of endings. -ate has more oxygen than -ite. Prefixes extend the set.
- Hypochlorite (ClO⁻)
- Chlorite (ClO₂⁻)
- Chlorate (ClO₃⁻)
- Perchlorate (ClO₄⁻)
Rule 4 — Roman numerals for variable charges
When a metal forms multiple cations you must show the charge. Copper(I) vs Copper(II). Iron(II) vs Iron(III).
Rule 5 — Parentheses for multiples of a polyatomic ion
Two or more of the same polyatomic group require parentheses in the formula. Barium nitrate appears as Ba(NO₃)₂.
Rule 6 — Hydrates show with a dot
Hydrates attach water molecules in a fixed ratio. The dot shows the association. Copper(II) sulfate pentahydrate is CuSO₄·5H₂O.
If you want a deep dive into preferred naming conventions see IUPAC’s concise resources and tutorials from the Royal Society of Chemistry.
Common ions cheat-sheet (responsive table)
You don’t need the entire periodic zoo to get started. This pared list covers the ions students meet most often.
| Ion | Charge | Name | Type |
|---|---|---|---|
| Na⁺ | +1 | Sodium | Cation |
| K⁺ | +1 | Potassium | Cation |
| Ca²⁺ | +2 | Calcium | Cation |
| Al³⁺ | +3 | Aluminum | Cation |
| Fe²⁺ | +2 | Iron(II) | Cation |
| Fe³⁺ | +3 | Iron(III) | Cation |
| NH₄⁺ | +1 | Ammonium | Polyatomic cation |
| Hg₂²⁺ | +2 | Mercury(I) | Diatomic cation |
| Cl⁻ | −1 | Chloride | Anion |
| O²⁻ | −2 | Oxide | Anion |
| S²⁻ | −2 | Sulfide | Anion |
| N³⁻ | −3 | Nitride | Anion |
| NO₃⁻ | −1 | Nitrate | Polyatomic anion |
| SO₄²⁻ | −2 | Sulfate | Polyatomic anion |
| CO₃²⁻ | −2 | Carbonate | Polyatomic anion |
| PO₄³⁻ | −3 | Phosphate | Polyatomic anion |
This table isn’t exhaustive. It covers the ions the calculator ships with by default so you get great coverage for most general chemistry tasks.
Worked examples
Follow these concise walkthroughs. They show how the calculator thinks.
Example 1 — Sodium + Chloride
- Cation: Na⁺. Anion: Cl⁻.
- LCM(1,1)=1. Subscripts both 1.
- Result: Sodium chloride, formula NaCl.
Example 2 — Calcium + Fluoride
- Cation: Ca²⁺. Anion: F⁻.
- LCM(2,1)=2. Ca gets 1, F gets 2.
- Result: Calcium fluoride, formula CaF₂.
Example 3 — Aluminum + Oxide
- Cation: Al³⁺. Anion: O²⁻.
- LCM(3,2)=6. Subscripts: Al₂O₃.
- Result: Aluminum oxide, formula Al₂O₃.
Example 4 — Iron(III) + Oxide
- Cation: Fe³⁺. Anion: O²⁻.
- LCM(3,2)=6. Fe₂O₃ again but name changes.
- Result: Iron(III) oxide, formula Fe₂O₃.
Example 5 — Ammonium + Sulfate
- Cation: NH₄⁺. Anion: SO₄²⁻.
- LCM(1,2)=2. Two ammonium ions.
- Result: Ammonium sulfate, formula (NH₄)₂SO₄.
Example 6 — Barium + Nitrate
- Cation: Ba²⁺. Anion: NO₃⁻.
- LCM(2,1)=2. Nitrate doubles with parentheses.
- Result: Barium nitrate, formula Ba(NO₃)₂.
Example 7 — Lead(IV) + Chloride
- Cation: Pb⁴⁺. Anion: Cl⁻.
- LCM(4,1)=4. Chloride quadruples.
- Result: Lead(IV) chloride, formula PbCl₄.
Example 8 — Mercury(I) + Chloride
- Cation: Hg₂²⁺. Anion: Cl⁻.
- Effective cation charge +2 as a dimer.
- Result: Mercury(I) chloride, formula Hg₂Cl₂.
Example 9 — Copper(I) + Oxide
- Cation: Cu⁺. Anion: O²⁻.
- LCM(1,2)=2. Two copper ions per oxide.
- Result: Copper(I) oxide, formula Cu₂O.
Example 10 — Copper(II) + Oxide
- Cation: Cu²⁺. Anion: O²⁻.
- LCM(2,2)=2. One to one.
- Result: Copper(II) oxide, formula CuO.
Example 11 — Lithium + Phosphate
- Cation: Li⁺. Anion: PO₄³⁻.
- LCM(1,3)=3. Three lithium ions.
- Result: Lithium phosphate, formula Li₃PO₄.
Example 12 — Magnesium + Hydroxide
- Cation: Mg²⁺. Anion: OH⁻.
- LCM(2,1)=2. Hydroxide doubles with parentheses.
- Result: Magnesium hydroxide, formula Mg(OH)₂.
Example 13 — Sodium + Sulfide
- Cation: Na⁺. Anion: S²⁻.
- LCM(1,2)=2. Two sodium ions per sulfide.
- Result: Sodium sulfide, formula Na₂S.
Example 14 — Potassium + Permanganate
- Cation: K⁺. Anion: MnO₄⁻.
- LCM(1,1)=1. No parentheses needed.
- Result: Potassium permanganate, formula KMnO₄.
Example 15 — Aluminum + Carbonate
- Cation: Al³⁺. Anion: CO₃²⁻.
- LCM(3,2)=6. Al₂(CO₃)₃ after balancing.
- Result: Aluminum carbonate, formula Al₂(CO₃)₃.
FAQs
What’s the difference between ionic and molecular names?
Ionic compounds use the cation–anion framework with charge balance. Molecular compounds use Greek prefixes to show exact counts like carbon dioxide or dinitrogen pentoxide. Each system fits a different bonding style.
When do I need Roman numerals?
Use them when the metal forms multiple common charges. Iron, copper, lead, and tin are classic examples. Group 1 and 2 metals don’t need numerals.
Why do some formulas have parentheses?
Parentheses group a polyatomic ion when you need more than one copy. You keep the group intact then place the subscript outside the parentheses.
Do I ever simplify subscripts?
Yes. If every subscript shares a common factor you divide to the lowest whole-number ratio. Cr₂O₄ reduces to CrO₂ although the real oxide of chromium aligns with standard oxidation states rather than raw arithmetic alone. Context matters in real compounds.
How do hydrates fit into names?
Add a Greek prefix then the word hydrate after the salt name. CuSO₄·5H₂O becomes copper(II) sulfate pentahydrate.
Troubleshooting and edge cases
Ambiguous metal charges
If you start with a name like “iron chloride” without a numeral you face an ambiguity. The calculator exposes both Fe²⁺ and Fe³⁺ options so you can choose the correct oxidation state then the name resolves to Iron(II) chloride or Iron(III) chloride.
Acids are different
Binary acids and oxyacids follow a related yet distinct naming scheme. Hydrochloric acid corresponds to HCl(aq). Nitric acid corresponds to HNO₃(aq). If you need acid names consult IUPAC guidance for aqueous acids which you can find through the Gold Book and education pages noted above.
Peroxides and superoxides
The oxide family holds special variants. Sodium peroxide is Na₂O₂ with peroxide O₂²⁻. Potassium superoxide is KO₂ with superoxide O₂⁻. Names encode the different anions.
Old “bi-” prefixes vs “hydrogen” names
Bicarbonate is an older name for hydrogen carbonate. Both refer to HCO₃⁻. Modern usage prefers hydrogen carbonate in formal contexts.
Hydrated and basic salts
Some salts include hydroxide in the lattice or bound water beyond a simple dot notation. Names show those features explicitly. The calculator focuses on core salt naming which covers most coursework.
Study tips and memory hooks
- Chunk oxyanion families. Learn chlorate then add prefixes to get the rest. The same trick works with bromate and iodate.
- Anchor common charges. Alkali metals are +1. Alkaline earth metals are +2. Aluminum is +3.
- Hear the rhythm. Metal first then nonmetal. Name then “-ide” or the oxyanion name. The cadence locks it in.
- Sketch mini tables. Two columns on a card for cations and anions beat a long list in your head.
- Practice with opposites. Pick an anion then try three different cations. You’ll see how subscripts jump with LCMs.
Why learners love a Chemical Name Calculator
Speed matters during study sessions. You want to verify answers then move on. The calculator handles the arithmetic cleanly with LCM logic then formats subscripts and parentheses for you.
Accuracy matters even more. Misplaced parentheses change compounds. Two nitrates around calcium turn CaNO₃₂ into nonsense while Ca(NO₃)₂ communicates the chemistry correctly. The tool protects you from that slip.
Clarity matters the most. The output shows the name and the formula side by side. You connect patterns faster which sticks for the exam.
Quick reference — prefixes and numerals you’ll see
| Roman numeral | Meaning | Used in |
|---|---|---|
| I | 1 | Copper(I), Iron(I) uncommon |
| II | 2 | Iron(II), Copper(II), Tin(II) |
| III | 3 | Iron(III), Aluminum(III) no numeral |
| IV | 4 | Lead(IV), Tin(IV) |
Roman numerals show oxidation state for metals with variable charges. Main group metals with a fixed charge usually skip the numeral.
From classroom to lab — where this tool shines
- Homework checks. Pick the ions then confirm the formula before you hand it in.
- Recipe planning. Preparing solutions requires the correct salt. You can confirm the name and the stoichiometry.
- Safety labels. Names must match containers. Quick verification lowers risk.
A mini walkthrough for deeper understanding
Take Aluminum sulfate. The ions are Al³⁺ and SO₄²⁻. The LCM of 3 and 2 equals 6. You need two aluminum ions and three sulfate ions. The formula becomes Al₂(SO₄)₃.
Try Ammonium phosphate. NH₄⁺ pairs with PO₄³⁻. The LCM of 1 and 3 equals 3. You place three ammonium ions around one phosphate which gives (NH₄)₃PO₄.
Test a tricky one like Mercury(I) nitrate. Mercury(I) is the dimer Hg₂²⁺. Nitrate is NO₃⁻. LCM of 2 and 1 equals 2. You keep the dimer intact then attach two nitrates which yields Hg₂(NO₃)₂.
Best practices when you write formulas
- Reduce subscripts only if they share a common factor and the reduced form matches a real compound.
- Keep the polyatomic group symbols standard. Students sometimes invent SO₂O for sulfite which breaks convention. Use SO₃²⁻.
- Place water in hydrates with a centered dot not a plus sign.
The Chemical Name Calculator shortens the path between what you recognize and what you need to write. Pick the ions. Get the proper name and the balanced formula. Practice a handful of examples and you’ll spot patterns that make nomenclature feel second nature.
Keep this page open while you work. When questions pop up scan the rules and the examples. You’ll move faster with fewer mistakes.
