Sodium azide

Sodium azide is the inorganic compound with the formula NaN3. This colorless salt is the gas-forming component in many car airbag systems. It is used for the preparation of other azide compounds. It is an ionic substance, is highly soluble in water, and is very acutely toxic. Sodium azide is the inorganic compound with the formula NaN3. This colorless salt is the gas-forming component in many car airbag systems. It is used for the preparation of other azide compounds. It is an ionic substance, is highly soluble in water, and is very acutely toxic. Sodium azide is an ionic solid. Two crystalline forms are known, rhombohedral and hexagonal. Both adopt layered structures. The azide anion is very similar in each form, being centrosymmetric with N–N distances of 1.18 Å. The Na+ ion has octahedral geometry. Each azide is linked to six Na+ centers, with three Na-N bonds to each terminal nitrogen center. The common synthesis method is the 'Wislicenus process', which proceeds in two steps from ammonia. In the first step, ammonia is converted to sodium amide: The sodium amide is subsequently combined with nitrous oxide: These reactions are the basis of the industrial route, which produced about 250 tons per year in 2004, with production increasing owing to the popularization of airbags.