Substance profile
Mercury
Mercury is a silver-white, heavy, mobile, liquid metal; solid mercury is tin-white and is odorless.
01 · Identification
What Mercury is
Mercury is a silver-white, heavy, mobile, liquid metal; solid mercury is tin-white and is odorless. Its molecular formula is Hg and its molecular weight is 200.59 g/mol. It boils at 357 °C, melts at -38.9 °C.
Under the GHS it carries the signal word Danger. It is classed as corrosives.
02 · Identifiers
Mercury identifiers and molecular data
Mercury CAS number and EC number
Mercury molecular formula and molecular weight
Other names for Mercury
- quicksilver
- Mercury Element
- Mercury Metal
- Mercury Metal: Colloidal Mercury
- Mercury, Metallic
- Metallic Mercury
- Quecksilber
03 · GHS classification
Mercury hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
Mercury pictograms and signal word
Mercury hazard class and category
| Hazard class | Category | From code | Pictogram |
|---|---|---|---|
| Acute toxicity - inhalation GHS chapter 3.1 | Category 1 or 2 | H330 | GHS06 |
| Specific target organ toxicity - repeated exposure GHS chapter 3.9 | Category 1 | H372 | GHS08 |
| Hazardous to the aquatic environment - acute GHS chapter 4.1 | Category 1 | H400 | GHS09 |
| Hazardous to the aquatic environment - chronic GHS chapter 4.1 | Category 1 | H410 | GHS09 |
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.
Mercury hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H360D | May damage the unborn child. |
| H330 | Fatal if inhaled. |
| H372 | Causes damage to organs <or state all organs affected, if known> through prolonged or repeated exposure <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>. |
| H400 | Very toxic to aquatic life. |
| H410 | Very toxic to aquatic life with long lasting effects. |
This page lists only the codes assigned to Mercury. 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 Mercury
Our own Mercury safety data sheet walks through all sixteen sections of the published data. What it is not is the document an inspector asks for: an SDS is issued for a product by its supplier, so the sheet covering the grade actually standing in your store exists only in that supplier’s version. Collecting those and keeping them current as suppliers revise them is a separate job.
04 · Precautionary statements
Mercury precautionary statements
CLP Annex VI assigns 9 precautionary statements to Mercury. 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.
Response
What to do once exposure, spillage or fire has already happened.
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
Mercury 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 | живак |
| Spanish español | Mercurio |
| Czech čeština | rtuť |
| Danish dansk | kviksølv |
| German Deutsch | Quecksilber |
| Estonian eesti | elavhõbe |
| Greek ελληνικά | υδράργυρος |
| English English | mercury |
| French français | mercure |
| Croatian hrvatski | živa |
| Italian italiano | mercurio |
| Latvian latviešu | dzīvsudrabs |
| Lithuanian lietuvių | gyvsidabris |
| Hungarian magyar | higany |
| Maltese Malti | merkurju |
| Dutch Nederlands | kwik |
| Polish polski | rtęć |
| Portuguese português | mercúrio |
| Romanian română | mercur |
| Slovak slovenčina | ortuť |
| Slovenian slovenščina | živo srebro |
| Finnish suomi | elohopea |
| Swedish svenska | kvicksilver |
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
Mercury GHS label elements
Everything CLP Annex VI fixes for Mercury, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Danger
Mercury
- May damage the unborn child.
- Fatal if inhaled.
- Causes damage to organs <or state all organs affected, if known> through prolonged or repeated exposure <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>.
- Very toxic to aquatic life.
- Very toxic to aquatic life with long lasting effects.
- Do not breathe dust/fume/gas/mist/vapours/spray.
- Do not eat, drink or smoke when using this product.
- Use only outdoors or in a well-ventilated area.
- Avoid release to the environment.
- IF INHALED:
- Immediately call a POISON CENTER/doctor/…
- Get medical advice/attention if you feel unwell.
- Collect spillage.
- Dispose of contents/container to …
Supplier name, address and telephone number· Product identifier·Nominal quantity
Need this as an actual label? Open Mercury in the GHS label constructor →
07 · Health hazards
Mercury health hazards and exposure limits
Mercury hazard summary
Mercurycombines with other elements, such as chlorine, sulfur, or oxygen, to form inorganic mercury compounds or "salts", which are usually white powders or crystals. Mercury also combines with carbon to make organic mercury compounds. The most common one, methylmercury, is produced mainly by microscopic organisms in the water and soil. More mercury in the environment can increase the amounts of methylmercury that these small organisms make.Metallic Mercuryis a dense liquid that vaporizes easily at room temperature. Metallic mercury is not easily absorbed into unbroken skin. However, it vaporizes, even at room temperature. The higher the temperature, the more vapors are released. Mercury vapors are colorless and odorless, though they can be seen with the aid of an ultraviolet light.Metallic mercury is used to produce chlorine gas and caustic soda, and is also used in thermometers, dental fillings, and batteries. Mercury salts are sometimes used in skin lightening creams and as antiseptic creams and ointments.
Source: Agency for Toxic Substances and Disease Registry (ATSDR)
Mercury carcinogenicity classification
Cancer Classification: Group D Not Classifiable as to Human Carcinogenicity
Source: Hazardous Substances Data Bank (HSDB)
An IARC group and a CLP classification answer different questions. IARC judges whether the evidence for cancer in humans is strong enough; CLP Annex VI is the legally binding EU classification. A substance can carry one and not the other.
Mercury occupational exposure limits
| Limit | Value | Source |
|---|---|---|
| PEL | 0.1 [mg/m3], as Hg | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| PEL | 0.01 mg/m³ | Occupational Safety and Health Administration (OSHA) |
| PEL | 0.04 mg/m³ | Occupational Safety and Health Administration (OSHA) |
| REL | 0.01 mg/m³ | Occupational Safety and Health Administration (OSHA) |
| REL | 0.03 mg/m³ | Occupational Safety and Health Administration (OSHA) |
| REL | 0.05 mg/m³ (Hg vapor) | Occupational Safety and Health Administration (OSHA) |
| IDLH | 10 mg Hg/m3 (NIOSH, 2024) | CAMEO Chemicals |
| IDLH | 10.0 [mg/m3], as Hg | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| IDLH | Excerpts from Documentation for IDLHs: A single 4 hr. dose of 28.8 mg/m3 of mercury vapor caused severe damage to the kidneys, lungs and colon of rabbits, while a one hr. exposure caused mild injury. | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
These are United States values. The European Union sets its own indicative and binding limits, and the figure that applies at a given workplace is the one in the local regulation — not the one shown here.
08 · Physical and chemical properties
Mercury 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.
Mercury boiling point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | 356.73 °C (674.1 °F) | HSDB | |
| 356.67 °C (674 °F) | NIOSH | ||
| 357.22 °C (675 °F) | at 760 mmHg | CAMEO |
Mercury melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | -38.87 °C (-38 °F) | HSDB | |
| -38.89 °C (-38 °F) | NIOSH |
Mercury density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 13.6 g/cm³ | metal | NIOSH |
| 13.55 g/cm³ | at 20 °C | CAMEO | |
| 13.534 g/cm³ | at 25 °C | HSDB |
Mercury solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | SOL IN NITRIC ACID; INSOL IN THE FOLLOWING: DILUTE HYDROCHLORIC ACID, HYDROGEN BROMIDE, HYDROGEN IODIDE, COLD SULFURIC ACID | HSDB | |
| DISSOLVES TO SOME EXTENT IN LIPIDS | HSDB | ||
| 0.28 umoles/l of water at 25 °C | at 25 °C | HSDB |
Mercury vapor pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor pressure | 0.0012 mmHg | NIOSH | |
| 0.002 mmHg | at 25 °C | HSDB |
Mercury autoignition temperature
| Property | Value | Conditions | Source |
|---|---|---|---|
| Autoignition temperature | Not flammable (USCG, 1999) | CAMEO |
Mercury lower explosive limit (LEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Lower explosive limit (LEL) | Metal: Noncombustible Liquid | NIOSH |
Mercury vapor density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor density | 6.93 (air = 1) | ICSC |
Mercury critical temperature and pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Critical temperature and pressure | 1462 °C (2663.6 °F) | HSDB |
Mercury corrosivity
| Property | Value | Conditions | Source |
|---|---|---|---|
| Corrosivity | Special precautions: Mercury can attack copper and copper alloy materials. | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
09 · Source notes
Further notes on Mercury
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.
Corrosivity
The high mobility and tendency to dispersion exhibited by mercury, and the ease with which it forms alloys (amalga) with many laboratory and electrical contact metals, can cause severe corrosion problems in laboratories.
Source: HSDB
10 · Handling and storage
Mercury storage and handling
Mercury reactive group
CAMEO Chemicals places Mercury in the reactive group Metals, Less Reactive. Compatibility with other chemicals is worked out from the group, not from the individual substance — which is why two substances you have never seen react can still be flagged as a pair that must be separated.
A reactive group is a CAMEO Chemicals (US NOAA) grouping, not a GHS hazard class: it has no code, no category and no legal force. It is what the storage compatibility matrix on this site computes from.
Mercury safe storage
Provision to contain effluent from fire extinguishing. Separated from food and feedstuffs. Well closed. Store in an area without drain or sewer access.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
Mercury storage conditions
Storage temperature: Ambient; Venting: Open
Source: Hazardous Substances Data Bank (HSDB)
Mercury incompatible materials
Ground mixtures of sodium carbide and mercury, aluminum, lead, or iron can react vigorously.
Source: Hazardous Substances Data Bank (HSDB)
Mercury reactivity
MERCURY forms an explosive acelylide when mixed with acetylene. Can form explosive compounds with ammonia (a residue resulting from such a reaction exploded when an attempt was made to clean it off a steel rod [Chem. Eng. News 25:2138. 1947]. Chlorine dioxide (also other oxidants, such as: chlorine, bromine, nitric acid, performic acid), and mercury explode when mixed [Mellor 2, Supp. 1:381. 1956]. Methyl azide in the presence of mercury is potentially explosive [Can. J. Chem. 41:1048. 1963]. Ground mixtures of sodium carbide and mercury can react vigorously [Mellor 5:848. 1946-47]. Ammonia forms explosive compounds with gold, mercury, or silver. (Eggeman, Tim. "Ammonia". Kirk-Othmer Encyclopedia of Chemical Technology. John Wiley & Sons, Inc. 2001.).
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Mercury in the storage compatibility matrix →
11 · Transport
Mercury 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.
Mercury under UN 2809 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| MERCURY | 8 | CT1 | III | |
Source: ADR 2025, Table A of Chapter 3.2 · ECE/TRANS/352 Vol. I (UNECE). Class 8 is “Corrosive substances” (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) |
|---|---|---|---|
| Mercury | 8 | III | |
Source: 49 CFR 172.101 Hazardous Materials Table · eCFR, revision 2026-08-03. Class 8 is “Corrosive material” (49 CFR 173.2).
12 · Questions
Mercury — frequently asked questions
What is the CAS number of Mercury?
The CAS number of Mercury is 7439-97-6. Its EC number is 231-106-7.
What is the chemical formula of Mercury?
The molecular formula of Mercury is Hg and its molecular weight is 200.59 g/mol.
What does a Mercury label have to show?
Under CLP Annex VI the label for Mercury carries the pictograms Skull and crossbones, Health hazard and Environment and the signal word is Danger.
Is Mercury flammable?
CLP Annex VI assigns Mercury no flammability hazard class. That is not a statement that it cannot burn: the harmonised list only records the hazards that were assessed for it.
Is Mercury a carcinogen?
CLP Annex VI records no harmonised carcinogenicity classification for Mercury. 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. IARC places it in Group 3: not classifiable as to its carcinogenicity to humans.
What is the exposure limit for Mercury?
The US occupational exposure limit reported for Mercury is 0.1 [mg/m3], as Hg (Haz-Map, Information on Hazardous Chemicals and Occupational Diseases). Limits differ by country: the EU sets its own indicative and binding values, and the figure that applies at a given workplace is the one in the local regulation.
What is the boiling point of Mercury?
The boiling point reported for Mercury is 356.73 °C (674.1 °F) (HSDB).
What is the melting point of Mercury?
The melting point reported for Mercury is -38.87 °C (-38 °F) (HSDB).
How should Mercury be stored?
Storage temperature: Ambient; Venting: Open (Hazardous Substances Data Bank (HSDB))
Nearby
Substances next to Mercury
Keep going: substances starting with M, or search the whole database by name, CAS number, pictogram or signal word.
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