Mercury -fulminate

Mercury fulminate (MF) is the oldest initiatory explosive known. 

The mercury fulminate (MF) formula is HgCC N —0 )2 with a covalent bond between the mercury and carbon atoms [20]. Its crystal density is reported to be 4.42-4.43 g cm [29, 30, 39, 40], but recent results of X-ray analysis updated it to 4,467 g cm [21]. Bulk density depends on crystal size and shape—it is reported to be between 1.35 and 1.55 g cm [38]. The heat of formation of MF is reported as being between —268 and —273 kJ moP [29, 41, 42]. The structure of the MF molecule and its crystal was published recently by Beck et al. [21]. Pure and ordinarily prepared mercury fulminate is, for all practical purposes, not hygroscopic, but its hygroscopicity rapidly increases in presence of impurities (e.g., mercury oxalate, calomel, mercuric chloride), which are generally present in the industrial 

The taste of MF is described variously as a sweetish metallic taste by some authors [38] or salty by WaUce [12], MF is, however, a very toxic substance [38]. 

MF is known to exist in various forms depending on the way of preparation. Many authors mention two forms—white and gray [15, 28]. In reality there are three forms—white, brown, and gray—obtained directly from the reaction mixture (see Fig. 3.1) and other forms obtained by recrystallization from various solvents (Pachman and Maty as unpublished work). 

The most common types of MF and the relations among them are schematically summarized in Fig. 3.2. Some authors misleadingly refer to the brown form as being gray [15, 28]. The white and brown forms are both desired products and are purer than the gray form which is produced by improperly carrying out the reaction. The brown form of MF is, contrary to general expectation, a little bit purer than the white form [16, 44]. 

The brown product with a well-developed crystal structure (Fig. 3.3) is formed when the reaction is carried out without any additives. Temperatures as well as concentrations and amounts of reacting substances must be optimized. 

After another major explosion in 1866 which completely demolished the nitroglycerine factory, Alfred turned his attentions into the safety problems of transporting nitroglycerine. To reduce the sensitivity of nitroglycerine Alfred mixed it with an absorbent clay, Kieselguhr . This mixture became known as ghur dynamite and was patented in 1867. 

Nitroglycerine (1.1) has a great advantage over blackpowder since it contains both fuel and oxidizer elements in the same molecule. This gives the most intimate contact for both components. 

Mercury fulminate was first prepared in the 17th century by the Swedish-German alchemist, Baron Johann Kunkel von Lowenstern. He obtained this dangerous explosive by treating mercury with nitric acid and alcohol. At that time, Kunkel and other alchemists could not find a use for the explosive and the compound became forgotten until Edward Howard of England rediscovered it between 1799 and 1800. Howard examined the properties of mercury fulminate and proposed its use as a percussion initiator for blackpowder and in 1807 a Scottish Clergyman, Alexander Forsyth patented the device. 

ERA Classified Acnte Hazardous Waste, RCRA Waste Number P065 DOT Label (wetted with not less than 20% by weight of water) Class A Explosive, UN 0135. 

COPPER(ll)FULMINATE 595 TABLE 30.1 Alkali-Metal Acetylides 

Mercury fulminate is used as a primary explosive to initiate boosters. 

White cubic crystals explodes on heating density 3.6 g/cm slightly soluble in water. 

Mercury fulminate is a highly toxic compound, exhibiting the toxicity symptoms of mercury. No toxicity data are available on this compound. 

Mercury fulminate was first prepared in the 17th century by the Swedish-German alchemist, Baron Johann Kunkel von Lowenstem. 

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Initiators. Explosives such as mercury fulminate and certain metallic azides which are extremely sensitive to mechanical shock, and are accordingly used in small quantities in detonators to initiate the explosion of larger masses of less sensitive material. 

Ereezing salt, see Sodium chloride Eulminating mercury, see Mercury fulminate... 

Mercury Fulminate. Mercury fulminate [628-86 ] Hg(CNO)2, slowly decomposes when stored at elevated temperature. Although... 

Explosives. Mercury, in the form of organic complexes, eg, mercury fulminate [628-86-4] has had long usage in explosives (see Explosives and propellants). In the United States all mercury for use in explosives is diverted to military uses. An explosive based on mercuric 5-nitrotetra2ole [60345-95-1] has been developed, but its use is on a small scale and in research and development only (3). 

Nitroglycerin was discovered by Ascanio Sobrero, in 1846. Its danger made it a laboratoiy curiosity until Alfred Nobel improved it along with other inventions such as the blasting cap ing mercury fulminate. 

On the other hand, for low shock-resistant expls such as Pb Azide, Mercury Fulminate or... 

Not detonated by 0.35g of Lead Azide and 0.2g of Tetryl, or by 0.5g of Mercury Fulminate 6 minutes Good... 

The primary mixt widely used by the US Army for small arms ammo in the early period of 1900 was based on Mercury Fulminate (MF) and is believed to be of Austrian origin (Ref 2), The most widely used formula is reported to have been as follows ... 

Gamer and Hailes [462] postulated a chain branching reaction in the decomposition of mercury fulminate, since the values of n( 10—20) were larger than could be considered consistent with power law equation [eqn. (2)] obedience. If the rate of nucleation is constant (0 = 1 for the generation of a new nuclei at a large number of sites, N0) and there is a constant rate of branching of existing nuclei (ftB), the nucleation law is... 

The decomposition kinetics of mercury fulminate [725] are significantly influenced by ageing, pre-irradiation and crushing these additional features of reaction facilitated interpretation of the observations and, in particular, the role of intergranular material in salt breakdown. Following a slow evolution of gas ( 0.1%) during the induction period, the accelerator process for the fresh salt obeyed the exponential law [eqn. (8)] when a < 0.35. The induction period for the aged salt was somewhat shorter and here the acceleratory process obeyed the cube law [eqn. (2), n = 3] and E = 113 kj mole-1. 

Mercury cyanide, 5, 1062 Mercury electrodes potential range aqueous solution, 1, 480 Mercury fluoride, 5. 1059 Mercury fulminate, 2, 7, 12 5, 1063 Mercury halides, 5, 1049 Mercury iodate, 5,1068 Mercury iodide, 5. 1059 Mercury ions Hgf... 

Fulminating gold Fulminating mercury Fulminating platinum Fulminating silver Fulminic acid Furan... 

With polyhaloalkanes, potassium forms mixtures that detonate on impact. The potassium/carbon tetrachloride mixture is hundred and fifty to two hundred times more sensitive than mercury fulminate. A simple door slam can cause its detonation. 

Nitroglycerine and other high explosives of this type are difficult to initiate into detonation simply by the use of a flame. Mercury fulminate, discovered by Howard, is an explosive of relatively low power which can, however, always be relied on to detonate when ignited by a flame. Explosives like mercury fulminate are known as initiating explosives. 

Mercury fulminate has the formula Hg(ONC)2. It was probably discovered by Howard in 1800 and its constitution was established by Nef. The method of preparation is known as the Chandelon process and is a complex reaction studied by Wieland. Mercury is dissolved in an excess of warm nitric acid and ethyl alcohol added to the resulting solution. Considerable bubbling occurs in the strong reaction, so this is usually carried out in capacious glass balloons . At the end of the reaction the mercury fulminate remains as a dense precipitate which is filtered and washed several times. 

Mercury fulminate is a pale brownish solid, insoluble in cold water, but dissolving slightly in hot water to a solution which does not give the normal mercury reactions. In cold conditions it is stable, but at higher temperatures gradually decomposes and loses strength as an explosive. It has a density of 4-45 g ml-1 and a velocity of detonation, when compressed to a practical density of 2-5, of about 3600 m s-1. 

When used in detonators, mercury fulminate is frequently mixed with 10 or 20% of potassium chlorate. Such mixtures have a better oxygen balance and therefore give improved and more reliable initiation of other explosives. 

Lead azide has virtually supplanted mercury fulminate in the... 

The original initiating explosive used by Nobel and all manufacturers for many years was mercury fulminate. This had the disadvantage of decomposing slowly in hot climates, particularly under moist conditions. For this reason mercury fulminate is no longer widely used. In most countries it has been replaced by a mixture of dextrinated lead azide and lead styphnate. In the U.S.A. some detonators are made containing diazodinitrophenol. 

The initiating explosive used must ignite with certainty from the spit of a safety fuse. It must be remembered that the intensity of the spit can be reduced if the safety fuse is not cut squarely and also that the fuse may in practice not always be fully inserted into the detonator. Lead azide by itself is not sufficiently easily ignited to give a satisfactory plain detonator and it is therefore used in admixture with lead styphnate, which is very readily ignited by flame. The proportions of such mixtures vary from 25 to 50% of lead styphnate. Mercury fulminate and diazodinitrophenol are sufficiently sensitive to flame not to require such additives. 

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