Azide

As azide is referred to the salts and organic compounds of hydrazoic acid. They belong to the pseudohalides. Many azides are highly toxic. The soluble salts inhibit irreversibly the enzyme cytochrome c oxidase of the respiratory chain in cells.

Schwermetallazide are highly explosive, the azides of alkali and alkaline earth metals, however fizzle out only at the effects of heat, after they have already melted.

The most important ionic azides are sodium azide and lead azide.

Inorganic azides

Sodium azide

Sodium azide is a colorless, water-soluble compound. Sodium azide is highly diluted used as preservatives, for example in the processing of perishable substances such as insulin, and as raw material for the manufacture of other azides and the free hydrazoic acid. It is also used in the iodine -azide reaction for the detection of divalent sulfur in the sulphides and thioethers. Furthermore, it is used in " air bag" for filling the bag. The decomposition can be initiated by heating, or an electrical pulse ( in air bag), and proceeds according to the following stoichiometric equation:

Lead azide

Lead azide is stable insoluble in cold water and to heat and moisture. Slow cooling of hot aqueous solutions results in long crystals, which already detonate upon breaking under water. Therefore, in the industrial production by adding a little dextrin and stirring, the formation of larger crystals strictly avoided. Its detonation point is 350 ° C. It is prepared by precipitation of sodium azide with a water-soluble lead salt such as lead acetate compound. Lead azide is used in a mixture with lead trinitroresorcinate, as primer. The latter is to increase the radio sensitivity as the detonation point of azide is high.

Silver azide

Silver azide is unlike lead azide when exposed to light much more unstable and turns in analogy to classical photography using silver halides quickly deep purple. For demonstration experiments it is more suitable as lead azide, as it is completely insoluble in hot water and always separates in fine crystals. The sensitivity to impact is not greater than that of the lead azide. Due to the high price but the application is available as an detonator used technically very limited.

Copper Azide

Copper azide is extremely disruptive and often explodes when touched. Therefore, there is no technical application and is unsuitable as a detonator.

Silicon tetraazide

Silicon tetraazide is a thermally unstable covalent silicon-nitrogen compound having a nitrogen content of 85.7 %. The high-energy, crystalline substance tends starting from 0 ° C to a spontaneous explosive decomposition. Another coordination to hexacoordinate structure as in Hexaazidosilicaten [Si (N3 ) 6] 2 -, or adducts with bivalent ligand Si ( N3) 4L2 leads to relatively stable, crystalline solids which can be handled normally at room temperature.

Organic azides

There are many organic compounds having an azido group ( - N3), which are thus referred to as organic azides. Methyl azide is the simplest representative of the organic azides. The tetrasubstituted methane derivative tetraazidomethane is a thermally unstable liquid having a nitrogen content of 93.3 %. The high-energy, prone to spontaneous explosive decomposition substance was first established in 2006. It is known the drug azidothymidine (AZT ). Carbonsäureazide [R -CO -N3 ] are used in the Curtius rearrangement, in which they are rearranged to form isocyanates. Another important reaction of azides, the 1,3-dipolar cycloaddition ( Huisgen reaction) dar. Known since the 1960s, she wins in the last decade become increasingly important as so-called bio-orthogonal reaction.