Substance profile
Calcium
Calcium is lustrous, silver-white surface (when freshly cut).
01 · Identification
What Calcium is
Calcium is lustrous, silver-white surface (when freshly cut). Its molecular formula is Ca and its molecular weight is 40.08 g/mol. It boils at 1484 °C, melts at 842 °C, is practically insoluble in water.
Under the GHS it carries the signal word Danger. It is classed as reactive agents - 2nd degree.
02 · Identifiers
Calcium identifiers and molecular data
Calcium CAS number and EC number
Calcium molecular formula and molecular weight
03 · GHS classification
Calcium hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
Calcium pictograms and signal word
Calcium hazard class and category
| Hazard class | Category | From code | Pictogram |
|---|---|---|---|
| In contact with water emits flammable gases GHS chapter 2.12 | Category 2 or 3 | H261 | GHS02 |
Where two values are shown with “or”, the hazard statement is shared by more than one category or by more than one class, and the code alone does not say which. H272, for example, belongs to oxidising liquids and to oxidising solids — the physical state decides. The binding answer for a specific entry is in the CLP Annex VI table itself.
Calcium hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H261 | In contact with water releases flammable gases. |
This page lists only the codes assigned to Calcium. The full reference lives on the hazard statements hub, the precautionary statements hub and the GHS pictograms hub.
Safety Data Sheet
Getting an SDS for Calcium
A Safety Data Sheet is written for a product, not for a substance: the supplier of the grade you actually buy issues it, so two suppliers of Calcium issue two different sheets. That is why there is no single authoritative SDS for a substance to download — what there is, is the job of collecting the sheets for the products you hold and keeping them current as suppliers revise them.
04 · Precautionary statements
Calcium precautionary statements
CLP Annex VI assigns 4 precautionary statements to Calcium. They are grouped the way a label groups them: what to do before handling, what to do when something has already happened, how to store it and how to dispose of it.
Prevention
What to do before and during handling so the hazard never happens.
Disposal
What has to happen to the contents and the empty container.
Reading the notation. … is a blank the supplier fills in — not a truncated sentence.· [square brackets] mark a part printed only when it applies.
05 · Names in the regulation
Calcium name in 23 EU languages
CLP Annex VI Part 3 is published in every language edition of the regulation, and the identification column is written out in each of them. Nothing below is translated by us: each line is the name as that edition prints it. Under Art. 18(2) the substance name from Annex VI is a lawful product identifier, so this is the wording to put on a label going to that market — and where the cell lists several designations, any one of them qualifies.
| Language | Name in CLP Annex VI Part 3 |
|---|---|
| Bulgarian български | калций |
| Spanish español | Calcio |
| Czech čeština | vápník |
| Danish dansk | calcium |
| German Deutsch | Calcium |
| Estonian eesti | kaltsium |
| Greek ελληνικά | ασβέστιο |
| English English | calcium |
| French français | calcium |
| Croatian hrvatski | kalcij |
| Italian italiano | calcio |
| Latvian latviešu | kalcijs |
| Lithuanian lietuvių | kalcis |
| Hungarian magyar | kálcium |
| Maltese Malti | kalċju |
| Dutch Nederlands | calcium |
| Polish polski | wapń |
| Portuguese português | cálcio |
| Romanian română | calciu |
| Slovak slovenčina | vápnik |
| Slovenian slovenščina | kalcij |
| Finnish suomi | kalsium |
| Swedish svenska | kalcium |
All 23 language editions of Annex VI carry this entry. Irish is the twenty-fourth official EU language and has no line here for a different reason: no consolidated CLP text has ever been published in Irish, so there is no Irish edition of Annex VI to quote a name from. Source: consolidated CLP, CELEX 02008R1272, language editions. © European Union, https://eur-lex.europa.eu — only the electronic Official Journal of the European Union is authentic.
06 · Label elements
Calcium GHS label elements
Everything CLP Annex VI fixes for Calcium, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Danger
Calcium
- In contact with water releases flammable gases.
- Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
- Handle and store contents under inert gas/…
- In case of fire:
- Dispose of contents/container to …
Supplier name, address and telephone number· Product identifier·Nominal quantity
Need this as an actual label? Open Calcium in the GHS label constructor →
07 · Health hazards
Calcium health hazards and exposure limits
Calcium hazard summary
Elemental calcium causes burns on contact with skin; [CAMEO] A single ingestion of calcium salts is not known to cause hypercalcemia or other systemic poisoning; Gastrointestinal hemorrhage after ingestion of calcium chloride has been reported; Hypercalcemia and renal failure have been reported after chronic ingestion of calcium carbonate. Rapid injection of calcium salts can cause cardiac arrhythmias and cardiac arrest; [HSDB]
Source: Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
08 · Physical and chemical properties
Calcium properties
Every value is shown with the conditions it was measured under and the source it came from. Where sources disagree, all values are listed rather than one being picked — the difference is usually a different form of the substance, not an error.
Calcium boiling point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | 1484 °C (2703.2 °F) | HSDB | |
| 1490 °C (2714 °F) | at 760 mmHg | CAMEO |
Calcium melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | 842 °C (1547.6 °F) | HSDB | |
| 850 °C (1562 °F) | CAMEO | ||
| 839 °C (1542.2 °F) | range, midpoint shown | ICSC |
Calcium density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 1.54 g/cm³ | at 20 °C | HSDB |
| 1.55 g/cm³ | at 20 °C | CAMEO | |
| 20 g/cm³ | at 20 °C | ICSC |
Calcium solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | Insoluble in benzene; reacts with water | HSDB | |
| Insoluble in and inert towards benzene, kerosene. | HSDB | ||
| Solubility in water: reaction | ICSC |
Calcium vapor pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor pressure | 10 mmHg | at 983 °C | HSDB |
| negligible | ICSC |
Calcium autoignition temperature
| Property | Value | Conditions | Source |
|---|---|---|---|
| Autoignition temperature | -27.78 °C (-18 °F) | CAMEO |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
09 · Fire and explosion
Calcium fire and explosion behaviour
These are descriptions rather than measured values, so they are kept out of the table above and quoted here with the source that reported them.
Calcium fire potential
Flammable when finely divided.
Source: Hazardous Substances Data Bank (HSDB)
10 · Handling and storage
Calcium storage and handling
Calcium safe storage
Fireproof. Dry. Well closed. Keep under inert gas. Separated from incompatible materials. See Chemical Dangers.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
Calcium storage conditions
Store in a cool, dry, well-ventilated location. Separate from water, alcohols, acids, and halogens. Immediately remove and properly dispose of any spilled material.
Source: Hazardous Substances Data Bank (HSDB)
Calcium incompatible materials
Calcium reacts violently with acids.
Source: Hazardous Substances Data Bank (HSDB)
Calcium reactivity
Boron trifluoride reacts with incandescence when heated with alkali metals or alkaline earth metals except magnesium [Merck 11th ed. 1989]. Calcium reacts violently with acids [Lab. Govt. Chemist 1965]. Finely divided calcium burns spontaneously in chlorine at elevated temperatures [Mellor 3:637, 638, 651 1946-47]. Finely divided or massive calcium burns spontaneously in fluorine at ordinary temperatures. It is incompatible with metal oxides, alkali metal hydroxides, chlorine fluorides, dinitrogen tetraoxide, and sulfur(with sulfur reacts explosively when ignited) [Bretherick, 5th Ed., 1995].
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Calcium in the storage compatibility matrix →
11 · Transport
Calcium UN number and transport classification
Transport classification is a separate system from the GHS classification above. It decides how a package is marked and how a load may be carried; it does not follow from the workplace label, and the workplace label does not follow from it. The entries below are linked by CAS number, never by name.
The same CAS number is shipped under more than one UN number. Which entry applies follows from the form and the concentration of the consignment — read the proper shipping name, not the CAS.
Calcium under UN 1401 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| CALCIUM | 4.3 | W2 | II | |
Source: ADR 2025, Table A of Chapter 3.2 · ECE/TRANS/352 Vol. I (UNECE). Class 4.3 is “Substances which, in contact with water, emit flammable gases” (ADR 2.1.1.1).
United States · 49 CFR 172.101 Hazardous Materials Table
| Proper shipping name (column 2) | Class or division | PG | Labels (column 6) |
|---|---|---|---|
| Calcium | 4.3 | II | |
Source: 49 CFR 172.101 Hazardous Materials Table · eCFR, revision 2026-08-03. Class 4.3 is “Dangerous when wet material” (49 CFR 173.2).
Calcium under UN 1855 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| CALCIUM, PYROPHORIC or CALCIUM ALLOYS, PYROPHORIC | 4.2 | S4 | I | |
Source: ADR 2025, Table A of Chapter 3.2 · ECE/TRANS/352 Vol. I (UNECE). Class 4.2 is “Substances liable to spontaneous combustion” (ADR 2.1.1.1).
United States · 49 CFR 172.101 Hazardous Materials Table
| Proper shipping name (column 2) | Class or division | PG | Labels (column 6) |
|---|---|---|---|
| Calcium, pyrophoric or Calcium alloys, pyrophoric | 4.2 | I | |
Source: 49 CFR 172.101 Hazardous Materials Table · eCFR, revision 2026-08-03. Class 4.2 is “Spontaneously combustible material” (49 CFR 173.2).
12 · Questions
Calcium — frequently asked questions
What is the CAS number of Calcium?
The CAS number of Calcium is 7440-70-2. Its EC number is 231-179-5.
What is the chemical formula of Calcium?
The molecular formula of Calcium is Ca and its molecular weight is 40.08 g/mol.
What does a Calcium label have to show?
Under CLP Annex VI the label for Calcium carries the pictogram Flame and the signal word is Danger.
Is Calcium flammable?
Yes. CLP Annex VI assigns Calcium H261 — in contact with water releases flammable gases.
Is Calcium a carcinogen?
CLP Annex VI records no harmonised carcinogenicity classification for Calcium. Annex VI is a list of agreed classifications, not a list of substances found safe, so this is an absence of a classification rather than a clean bill of health.
What is the boiling point of Calcium?
The boiling point reported for Calcium is 1484 °C (2703.2 °F) (HSDB).
What is the melting point of Calcium?
The melting point reported for Calcium is 842 °C (1547.6 °F) (HSDB).
How should Calcium be stored?
Store in a cool, dry, well-ventilated location. Separate from water, alcohols, acids, and halogens. Immediately remove and properly dispose of any spilled material. (Hazardous Substances Data Bank (HSDB))
Nearby
Substances next to Calcium
Keep going: substances starting with C, or search the whole database by name, CAS number, pictogram or signal word.