21. The structure consists of a linear azide substituent bound to a phenyl group. 22. The initial nucleophilic attack on the azide is the rate-limiting step. 23. Calcium phosphide and sodium azide were determined to be too difficult to procure. 24. Not all of the sodium azide gets recycled. 25. Sodium azide shipments to Butterfield began in September 1995 and ended one year later. 26. The azide -containing pyrotechnic gas generators contain a substantial amount of the propellant. 27. Once the ring is heated the barium azide decomposes into barium vapor and nitrogen. 28. The overall conversion is a mild method of reducing an azide to an amine. 29. It is one of the prototypical organic azides . 30. The Bergmann degradation makes use of the azide degradation described by the Curtius rearrangement.