Lead azide, Pb (N3) 2, has a molecular mass of 291,23 g/mol and since its first use as initial explosive Martin) the most important initial explosive became, which displaced in former times usual mercury fulminate nearly completely. In addition despite smaller energy content and smaller density it has larger initial strength, is less impactsensitive than mercury fulminate and has a importantly larger stability at higher temperatures and against humidity. The introduction from aluminum to the blasting cap production and thus an important reducing in price were possible only by use of lead azide, since Quecksilberfulminat with aluminum forms amalgam.

Material data

• Spec. Weight 4.38 g/cm3
• Detonation speed: 4630 m/s
• Verpuffungspunkt: 340 "°C/10 s
• Heat of combustion: 630 cal/g
• Explosion warmth: 367 cal/g
• Sensitivity to impact after Koenen: 0,4
• Decrease in weight with 100 "°C after 2 days: 0.05%
• Moisture absorption with 30 "°C and 90% rel. Air humidity: 0.84%
• CAS number: 13424-46-9
• R and S-sentences: R 2-20/22-33; S 13-20/21

Production

Lead azide results from double conversion of water-soluble lead salts with salts of the nitrogen hydracid. Depending upon intended purpose by variation of the procedural conditions, for example the temperature, the concentration of the solutions and the kind of the lead salt, products are manufactured from colloidal structure to regularly trained crystals. The controlling of the crystal habit is supported still by additives, which affect the crystal growth in certain direction, for example Dextrin or polyvinyl alcohol. One is anxious to manufacture that lead azide form which serves its purpose under possible reduction of the dangers, which are connected with the use of such a sensitive explosive. The danger potential shows up in the fact that the azide is soluble in hot water and forms with the slow cooling long transparent crystals, which already detonate when breaking under water. For the same reason in practice no pure lead azide is used, but one manufactures products, which contain basic or other heavysoluble lead salts as "diluents ". At most used technical lead azide 87 per cent lead azide contains, about 5 per cent Dextrin and about 8 per cent lead hydroxide ways of the Giftigkeit of the Metallstaubes (lead), developed with the detonation, was with lecture attempts better silver azide to be demonstrated, which also harmless always develops in finest crystals.

Articles in category "Lead azide"

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