Substance profile
Sodium azide
Sodium azide is colorless hexagonal crystals and is odorless.
01 · Identification
What Sodium azide is
Sodium azide is colorless hexagonal crystals and is odorless. Its molecular formula is N3Na and its molecular weight is 65.01 g/mol. It melts at 275 °C, is slightly soluble in water.
Under the GHS it carries the signal word Danger. It is classed as reactive agents - 3rd degree.
02 · Identifiers
Sodium azide identifiers and molecular data
Sodium azide CAS number and EC number
Sodium azide molecular formula and molecular weight
Other names for Sodium azide
- NaN3
- Azide
- Azium
- Hydrazoic Acid, Sodium Salt
- Kazoe
- Nemazyd
- Smite
- Sodium Azide (Na(N3))
- Sodium Azide(Na(N3))
- Sodium Salt Of Hydrazoic Acid
- U-3886
03 · GHS classification
Sodium azide hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
Sodium azide pictograms and signal word
Sodium azide hazard class and category
| Hazard class | Category | From code | Pictogram |
|---|---|---|---|
| Acute toxicity - oral GHS chapter 3.1 | Category 1 or 2 | H300 | GHS06 |
| 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.
Sodium azide hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H300 | Fatal if swallowed. |
| H400 | Very toxic to aquatic life. |
| H410 | Very toxic to aquatic life with long lasting effects. |
Sodium azide supplemental EU statements (EUH)
| Code | Statement |
|---|---|
| EUH032 | Contact with acids liberates very toxic gas. |
This page lists only the codes assigned to Sodium azide. 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 Sodium azide
Our own Sodium azide 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
Sodium azide precautionary statements
CLP Annex VI assigns 7 precautionary statements to Sodium azide. 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
Sodium azide 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 | натриев азид |
| Spanish español | Azida de sodio |
| Czech čeština | azid sodný |
| Danish dansk | natriumazid |
| German Deutsch | Natriumazid |
| Estonian eesti | naatriumasiid |
| Greek ελληνικά | νατραζίδιο |
| English English | sodium azide |
| French français | azoture de sodium |
| Croatian hrvatski | natrijev azid |
| Italian italiano | azoturo di sodio |
| Latvian latviešu | nātrija azīds |
| Lithuanian lietuvių | natrio azidas |
| Hungarian magyar | nátrium-azid |
| Maltese Malti | ażur tas-sodju |
| Dutch Nederlands | natriumazide |
| Polish polski | azydek sodu |
| Portuguese português | azida de sódio |
| Romanian română | azidă de sodiu |
| Slovak slovenčina | azid sodný |
| Slovenian slovenščina | natrijev azid |
| Finnish suomi | natriumatsidi |
| Swedish svenska | natriumazid |
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
Sodium azide GHS label elements
Everything CLP Annex VI fixes for Sodium azide, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Danger
Sodium azide
- Fatal if swallowed.
- Very toxic to aquatic life.
- Very toxic to aquatic life with long lasting effects.
- Contact with acids liberates very toxic gas.
- Do not eat, drink or smoke when using this product.
- Avoid release to the environment.
- IF SWALLOWED:
- Immediately call a POISON CENTER/doctor/…
- Rinse mouth.
- Collect spillage.
- Dispose of contents/container to …
Supplier name, address and telephone number· Product identifier·Nominal quantity
Need this as an actual label? Open Sodium azide in the GHS label constructor →
07 · Health hazards
Sodium azide health hazards and exposure limits
Sodium azide hazard summary
Azide is a potent vasodilator that has been used as an antihypertensive drug. Disposal of sodium azide in drain pipes can cause an explosive hazard for plumbers. [ACGIH] See Merck Index # 8581. In high-dose animal studies, sodium azide causes increased fetal loss. [Frazier, p. 361-2] As used in automobile airbags, sodium azide reacts at impact to produce nitrogen gas and to fill the air bag. When poured down a drain, sodium azide reacts with water to form hydrogen azide (hydrazoic acid). It can also react with lead pipes or lead solder to form lead azide. Both of these compounds are highly explosive. The azide group (N3) has an affinity for ferric iron in mitochondrial cytochrome oxidase. Like cyanide poisoning, azide poisoning disrupts cellular aerobic metabolism. Azide solutions are alkaline and corrosive to the eyes. Patients contaminated with liquids or solid material should be washed with soap and water after removal of clothing. There are no specific antidotes for azide poisoning. [AHLS, p. 202, 218-20] Doses of 0.65-3.9 mg/day were given as an experimental hypertensive drug--hypotensive effect within 1 minute and headache was only complaint; Ingestion of several grams causes death within 1-2 hours. Sodium azide is a respiratory irritant, and dust or fumes can induce pulmonary edema. [Olson, p. 148] See AZIDES.
Source: Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
Sodium azide carcinogenicity classification
Under the conditions of these 2-year gavage studies, there was no evidence of carcinogenic activity of sodium azide in male or female F344/N rats administered 5 or 10 mg/kg.
Source: US National Toxicology Program · TR-389: Toxicology and Carcinogenesis Studies of Sodium Azide (CASRN 26628-22-8) in F344 Rats (Gavage Studies) (1991 )
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.
Sodium azide occupational exposure limits
| Limit | Value | Source |
|---|---|---|
| PEL | none See Appendix G | The National Institute for Occupational Safety and Health (NIOSH) |
| REL | 0.1 ppm (0.3 mg/m³) (as HN3), 0.3 mg/m³ (as NaN3) | Occupational Safety and Health Administration (OSHA) |
| REL | C 0.1 ppm (as HN3) [skin] C 0.3 mg/m3 (as NaN3) [skin] | The National Institute for Occupational Safety and Health (NIOSH) |
| IDLH | N.D. | The National Institute for Occupational Safety and Health (NIOSH) |
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
Sodium azide 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.
Sodium azide boiling point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | Decomposes | decomposes | NIOSH |
| Decomposes in vacuum (EPA, 1998) | decomposes | CAMEO | |
| decomposes | decomposes | OSHA |
Sodium azide melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | 275 °C (527 °F) | decomp | HSDB |
| 275 °C (527 °F) | decomposes | NIOSH |
Sodium azide density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 1.85 g/cm³ | NIOSH | |
| 1.846 g/cm³ | at 20 °C | HSDB |
Sodium azide solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | Slightly soluble in ethanol, insoluble in ethyl ether | HSDB | |
| Slightly soluble in alcohol; insoluble in ether; soluble in liquid ammonia | HSDB | ||
| 50 to 100 mg/mL at 72 °F (NTP, 1992) | at 22.22 °C | CAMEO |
Sodium azide vapor pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor pressure | 0.0075 mmHg | at 20 °C | HSDB |
Sodium azide flash point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Flash point | Not flammable (EPA, 1998) | CAMEO |
Sodium azide lower explosive limit (LEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Lower explosive limit (LEL) | May explode when heated above its melting point, especially if heating is rapid. | HSDB | |
| Combustible Solid (if heated above 572 °F). | NIOSH | ||
| Insensitive to impact, it decomposes, sometimes explosively, above mp, particularly if heated rapidly. | decomposes | HSDB |
Sodium azide corrosivity
| Property | Value | Conditions | Source |
|---|---|---|---|
| Corrosivity | Very corrosive to aluminum, moderate to copper and lead | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
09 · Fire and explosion
Sodium azide 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.
Sodium azide fire potential
Combustible solid (if heated above 300 °C).
Source: Hazardous Substances Data Bank (HSDB)
10 · Handling and storage
Sodium azide storage and handling
Sodium azide reactive group
CAMEO Chemicals places Sodium azide in the reactive group Azo, Diazo, Azido, Hydrazine, and Azide Compounds. 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.
Sodium azide safe storage
Separated from food and feedstuffs, acids and metals. See Chemical Dangers. Provision to contain effluent from fire extinguishing. Store in an area without drain or sewer access.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
Sodium azide storage conditions
Keep container tightly closed in a dry and well-ventilated place. Never allow product to get in contact with water during storage. Do not store near acids.
Source: Hazardous Substances Data Bank (HSDB)
Sodium azide incompatible materials
Incompatible materials: Halogenated hydrocarbon, metals, acids, acid chlorides, hydrazine, dimethyl sulfate, inorganic acid chlorides.
Source: Hazardous Substances Data Bank (HSDB)
Sodium azide reactivity
SODIUM AZIDE is unstable. Decomposes rapidly or explosively at about 300 °C [Hawley]. May explode if shocked. Forms violently explosive products if exposed to carbon disulfide. Can be sensitized toward decomposition by metal salts (especially heavy metal salts such as silver chloride) or by traces of strong acids [Sax, 9th ed., 1996, p. 298].
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Sodium azide in the storage compatibility matrix →
11 · Transport
Sodium azide 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.
Sodium azide under UN 1687 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| SODIUM AZIDE | 6.1 | T5 | II | |
Source: ADR 2025, Table A of Chapter 3.2 · ECE/TRANS/352 Vol. I (UNECE). Class 6.1 is “Toxic 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) |
|---|---|---|---|
| Sodium azide | 6.1 | II | |
Source: 49 CFR 172.101 Hazardous Materials Table · eCFR, revision 2026-08-03. Class 6.1 is “Poisonous materials” (49 CFR 173.2).
12 · Questions
Sodium azide — frequently asked questions
What is the CAS number of Sodium azide?
The CAS number of Sodium azide is 26628-22-8. Its EC number is 247-852-1.
What is the chemical formula of Sodium azide?
The molecular formula of Sodium azide is N3Na and its molecular weight is 65.01 g/mol.
What does a Sodium azide label have to show?
Under CLP Annex VI the label for Sodium azide carries the pictograms Skull and crossbones and Environment and the signal word is Danger.
Is Sodium azide flammable?
CLP Annex VI assigns Sodium azide 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. The flash point reported for it is Not flammable (EPA, 1998) (CAMEO).
Is Sodium azide a carcinogen?
CLP Annex VI records no harmonised carcinogenicity classification for Sodium azide. 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 exposure limit for Sodium azide?
The US occupational exposure limit reported for Sodium azide is none See Appendix G (The National Institute for Occupational Safety and Health (NIOSH)). 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 Sodium azide?
The boiling point reported for Sodium azide is Decomposes, decomposes (NIOSH).
What is the melting point of Sodium azide?
The melting point reported for Sodium azide is 275 °C (527 °F), decomp (HSDB).
How should Sodium azide be stored?
Keep container tightly closed in a dry and well-ventilated place. Never allow product to get in contact with water during storage. Do not store near acids. (Hazardous Substances Data Bank (HSDB))
Nearby
Substances next to Sodium azide
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