Calcium azide, decomposition

The explosive properties of sodium, calcium, strontium and barium azides have been investigated at the Chemisch-Technische Reichsanstalt [135]. These azides differ markedly from lead, silver and cupric azides in that they show none of the properties of primary explosives. All three may be ignited by a spark, a glowing wire or the flame of blackpowder. Calcium azide bums most rapidly and has distinctly marked explosive properties. Larger quantities of it may explode when ignited in a closed tin, while strontium and barium merely bum violently. Calcium azide detonates under the influence of a detonating cap. The sodium azide does not decompose in these conditions. The other azides show weak decomposition under the influence of a standard (No. 3) detonator. Their most important properties are tabulated below. 

CaNe (c). Wohler and Martin1 measured the heat of decomposition of calcium azide. 

Barium azide may be obtained by any of the methods described for calcium azide. When precipitating the aqueous solution, acetone should be preferred as it yields a coarser product [132] which is less likely to contain impurities. The salt has also been synthesized with hydrazine and nitrite 3.5 g barium hydroxide and 200 ml aqueous hydrazine (5% w/w) were cooled with ice and 15 g ethyl nitrite added dropwise with stirring. The next day, excess hydroxide was removed with CO2 the filtrate yielded 8 g barium azide (30% of the theoretical yield) [49]. Small samples of barium azide have also been made according to the Wislicenus process the intermediate amide formed at 260-290°C and the azide at 140-175°C [85], which is, however, already within the range of thermal decomposition. 

Tompkins FC, Young DA (1965) Decomposition of calcium azide. Trans Faraday Soc 61 1470-1480... 

Endothermic-reactive compounds. Although this type of reaction is rare, some compounds are produced endothermically, that is, heat is absorbed into the reaction product rather than liberated. However, potentially no energy would be required to decompose these compounds, and their decomposition would release energy. These compounds are potentially unstable (acetylene, silver fulminate, calcium azide). 

Dining the preparation of cellular rubber by thermal decomposition of calcium, strontium or barium azides, various additives were necessary to prevent explosive decomposition of the azide in the blended mixture. 

Cesium is obtained from its ore pollucite. The element in pure form may be prepared by several methods (i) electrolysis of fused cesium cyanide, (ii) thermal reduction of cesium chloride with calcium at elevated temperatures, and (iii) thermal decomposition of cesium azide. It is stored under mineral od. The element must be handled under argon atmosphere. 

Wear face shield, goggles, laboratory coat, and nitrile rubber gloves. Cover spill with a 1 1 1 mixture by weight of sodium carbonate or calcium carbonate, clay cat litter (bentonite), and sand. Using a plastic shovel, scoop into a pail of water in the fume hood (about 66 mL/g). Cautiously add aqueous 5.5% ceric ammonium nitrate (4 volumes per volume of aqueous solution) and stir for an hour. If the solution remains orange, an excess of ceric ammonium nitrate is present and the azide has been completely destroyed. The solution can be washed into the drain with at least 50 times its volume of water.6,7 The solid residue is treated as normal refuse. A spot test for checking if azide is completely destroyed is as follows Place a drop of the test solution in the depression of a spot plate and treat with 1 or 2 drops of dilute hydrochloric acid. Add a drop of ferric chloride solution and gently heat the spot plate. A red color indicates hydrazoic acid and incomplete decomposition. 

MERCURIC BROMIDE (7789-47-1) HgBfj Noncombustible solid. Light and heat cause decomposition keep out of sunlight. Violent reaction with strong oxidizers, including chlorine trifluoride. Aqueous solution is acidic. Incompatible with acetylene, ammonia, azides (may form mercury azide, a heat- and shock-sensitive explosive), bases, caustics, amines, amides, inorganic hydroxides calcium (forms amalgam) carbide, chlorine dioxide, copper and its alloys hydrazines, indium (violent at 662°F/350°C), lithiiun, potassium, rabidium, sodium. Note Be especially careful not to allow this compound to accumulate in sink traps with many of the above incompatible... 

Cesium is an alkali metal that reacts explosively with water and melts just above room temperature. The word cesium is derived from caesium (Latin for sky blue ). The name was chosen because of the blue lines observed by Robert Bunsen and Gustav Kirchhoff during their analysis of springwater with a spectroscope in 1860. Currently, cesium metal is generated via thermal decomposition of the azide, electrolysis of molten CsCN, or reduction of molten CsCl with calcium vapor followed by fractional distillation. 

EXPLOSION and FIRE CONCERNS noncombustible slightly volatile at ordinary temperatures NFPA rating (not rated) may explode on contact with 3-bromopropyne, ethylene oxide, lithium, peroxyfonnic acid, and chlorine dioxide vapor ignites on contact with boron diiodophosphide reacts violently with acetylenic compounds, metals, chlorine, chlorine dioxide, methyl azide, and nitromethane incompatible with acetylene, ammonia, chlorine dioxide, azides, calcium, sodium carbide, lithium, rubidium, and copper heating to decomposition emits toxic fumes of Hg use water spray, fog, or foam for firefighting purposes. 

This formation of spontaneously ignitible strontium and barium has been reported by Tiede, He also mentions the decomposition of calcium and lithium azide under the same conditions, but remarks only that lithium azide is rather explosive on heating. 

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