Copper(II) azide
Copper Azide
Fixed
2.60 g · cm -3
Explodes at 215 ° C
Practically insoluble in water (80 mg · l-1 at 20 ° C)
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Copper azide is the copper salt of hydrazoic acid. It is explosive and is due to the high sensitivity to friction and pressure do not apply.
Production and modifications
According to Urbanski four modifications are known: The anhydrous compound is brown with a reddish glow. The green modification results from the action of hydrazoic acid to copper hydroxide or copper oxide. Sometimes it has a more gray color. Heating in water leads to hydrolysis under basic Kupferazids formation of a yellow color.
Brown - yellow form
The reaction of copper sulfate with sodium azide or by the action of a diluted hydrazoic acid on metallic copper produced by Theodor Curtius anhydrous copper (II ) azide in the form of brown - yellow, sparingly soluble in water crystals.
Green modification
It is formed by the action of hydrazoic acid on copper or ( Straumanis and Cirulis ) copper (II ) oxide. Sometimes it has a more gray color.
Yellow modification
Heating in water ( Wöhler and Krupko, 1913) leads to the formation of hydrolysis under basic Kupferazids. Very long warming caused by Straumanis and Cirulis the complete hydrolysis, copper and free acids are released.
Material data
- Detonation velocity: 5000-5500 m · s- 1
- Deflagration: 202-205 ° C
- Heat of combustion: 67.23 kcal · g -1
- Impact sensitivity: 2.66 kpm · cm -2
- Activation energy of 26.5 kcal · mol -1
Complex salts
The complex salts of Kupferazids are also explosive. So the salt Cu ( NH3) 4 (N3 ) 2 much less sensitive to impact (1 kg from a height of 20 cm). Exceptionally strong Initiiereigenschaften has the complex Lithiumhexaazidocuprat (II ) Li4 [Cu (N3 ) 6].
Use
Copper azide is one of the initiating explosives. The green modification is the most sensitive. They often already exploded on contact. Under the 2- kg drop hammer it explodes at a height of less than 1 cm. The black / brown modification at 1 cm, and the amber with a 1- kg drop hammer 7-8 cm. Noteworthy is the high Initiierfähigkeit for PETN, with only 0.4 mg of copper azide sufficient to bring the PETN detonation. Copper Azide has great practical significance, since it (I) azide may occur with prolonged exposure of lead azide to copper or its alloys as well as copper. Schwermetallazide be used as oxidizing agents in the laboratory.
Copper Azide has a smooth surface, but forms grooves with a width of 5 nm ( 110- direction). This property can be exploited to produce nanowires of iron, palladium or gold by vapor deposition.
Safety
Copper ( II) azide is very sensitive, and explodes at low pressure or friction. Since there are safer primary explosives, it should not be manufactured or used.