Sodium azide is a sodium salt with the chemical formula NaN3.



Sodium azide will decompose at temperatures over 300°C to yield nitrogen gas.

2 NaN3 → 2Na + 3 N2

In contact with a strong acid will release hydrazoic acid.

NaN3 + H+ → HN3 + Na+

Sodium azide can be destroyed by reacting it with nitrous acid

2 NaN3 + 2 HNO2 → 3 N2 + 2 NO + 2 NaOH


Sodium azide is a white odorless salt. Sodium azide is soluble in water (40.8 g/100 mL at 20 °C) and ammonia, but insoluble in acetone, ether, chloroform and hexane.


Sodium azide was used in the first car airbags, as the gas generator. It is usually mixed with either silica and iron(III) oxide so purification is required.


Industrially sodium azide is prepared via "Wislicenus process", by reacting sodium amide with nitrous oxide. Sodium amide is prepared by reacting metallic sodium with anhydrous ammonia.

2 Na + 2 NH3 → 2 NaNH2 + H2
2 NaNH2 + N2O → NaN3 + NaOH + NH3

As this method uses metallic sodium and inert conditions it is expensive for the amateur chemist.

A less complex synthesis involves the reaction of a nitrite ester with hydrazine:

R-ONO + N2H4 + NaOH → NaN3 + R-OH + 2 H2O

Another method discussed involves the reaction of sodium nitrite with urea under controlled conditions.


  • Generating pure nitrogen gas
  • Preparation of pure sodium



Sodium azide is extremely toxic. The toxicity of azides is similar that of cyanides, the lethal dose for an adult human is around 0.7 g.


Sodium azide should be stored in spark-free containers, away from moisture or any acidic vapors


When disposed of, it must never be poured down the drain, as it will react to either copper or lead plumbing to yield hydrazoic acid. Hydrolysis can also occur in aqueous solutions, at certain pH. Sodium azide must be treated with nitrous acid before being discarded.[1]



Relevant Sciencemadness threadsEdit

Community content is available under CC-BY-SA unless otherwise noted.