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.
- 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
- 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.