Metals hydrogen azide

Metallic cyanides, sodium azide and hydrogen azide form explosive mixtures with nitric acid. 

An ethereal solution of some 100 g of the crude nitrile was allowed to spontaneously evaporate and crystallise. The crystalline slurry so produced exploded violently without warning. Previously such material had been found not to be shock-sensitive to hammer blows, but dry recrystallised material was very shock-sensitive. Traces of free hydrogen azide could have been present, and a metal spatula had been used to stir the slurry, so metal azides could have been formed. See Other CYANO COMPOUNDS, ORGANIC AZIDES... 

The majority of the metal azides are sensitive explosives and exposure to heat, friction or impact is usually undesirable. Contact of most azides, particularly readily soluble ones, with acids will produce hydrogen azide, itself an explosive and highly toxic low-boiling liquid. In presence of heavy metals, it may give other equally hazardous heavy metal azides. These may also be formed from contact of soluble azides with heavy metals. 

In the presence of ammonia, the metal-azide unit can possibly undergo facile ammonolysis in the same way as alkyl-amide type precursors, but it produces HN3 instead of alkylamines. Hydrogen azide itself acts as a very efficient source for the N-component (see Eq. 5). In Ihe case of ammonolysis of metal azides in the gas phase, HN3 would be produced in situ only in the reactor close to the substrate surface, thus circumventing the intrinsic problems... 

Buell, McEwen, and Kleinberg have observed that weak acids such as hydrogen azide and acetic acid add readily across the double bond of vinylferrocene (XLI, M = Fe) (8). They have postulated that the mechanism of addition proceeds via intermediate formation of the a -ferrocenylcarbonium ion (X-LII, M = Fe), followed by conversion to the acetate (XLIII, M = Fe). Stabilization of carbonium ions of this type can result from overlap of filled metal orbitals with the vacant p -orbital of the carbonium ion. 

See related NON-METAL HYDRIDES 4435. Hydrogen azide (Hydrazoic acid)... 

Especially, trimethylazidosilane (TMSA) (452) is an excellent reagent for preparative purposes, since it can be applied to many reactions which otherwise require the application of the explosive hydrogen azide. A number of synthetic methods for the preparation of azidosilanes are known. Starting materials are mostly metal azides, which are applied to halogenosilanes in THF via this approach TMSA (452) is obtained in 81 % yield (equation 243)230, 258 from Me3SiCl. 

AZIDA de BARIO (Spanish) (18810-58-7) Highly unstable in dry form. Dust forms explosive mixture with air. Heat, shock, or friction can cause spontaneous decomposition and explosion. Forms shock-sensitive mixtures with lead and other heavy metals. Contact with barium, iron, or sodium will increase its sensitivity to explosion. Contact with acids forms corrosive hydrogen azide. Reacts violently with oxidizers, carbon disulfide. Commercially available in ethyl alcohol. Keeping the chemical wet greatly reduces its explosion hazard. 

AZIDA SODICA (Spanish) (26628-22-8) Reacts with hot water. Explosive decomposition in elevated temperatures above 525°F/274°C. Forms ultra-sensitive explosive compounds with heavy metals copper, copper alloys, lead, silver, mercury, carbon disulfide, trifluoroacryloyl fluoride. Violent reaction with acids, forming explosive hydrogen azide. Violent reaction with bromine, barium carbonate, chromyl chloride, dimethyl sulfate, dibromomalononitrile. Incompatible with caustics, cyanuric chloride, metal oxides, metal sulfides, methyl azide, phosgene. 

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