Chlorine azide

Chlorine azide (ClN3) is an inorganic compound that was discovered in 1908 by Friedrich Raschig. 
Concentrated is notoriously unstable and may spontaneously detonate at any temperature.
Preparation and handling.
Chlorine azide is prepared by passing chlorine gas over silver azide, or by an addition of acetic acid to a solution of sodium hypochlorite and sodium azide.
When treated with ammonia it is conceivable that one or more of the three possible azinamines, NH2N3, NH(N3)2, and N(N3)3 may be formed.
Explosive characteristics.
Chlorine azide is extremely sensitive. It may explode, sometimes even without apparent provocation; it is thus too sensitive to be used commercially unless first diluted in solution. Chlorine azide reacts explosively with 1,3-butadiene, ethane, ethene, methane, propane, phosphorus, silver azide, and sodium. On contact with acid, chlorine azide decomposes, evolving toxic and corrosive hydrogen chloride gas.
Regulatory information.
Its shipment is subject to strict reporting requirements and regulations by the US Department of Transportation.