MF = mercury fulminate

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 ... 

Sensitivity to initiation non-compressed HN with 0.5% moisture content, detonated with a cap contg 0.25g Mercury Fulminate compressed to d 1.60, 1.5g MF was required for detonation (Ref 8)... 

Mercury Fulminate (MF) (1346) Diazodinitrophenol (DAzDNPh or DDNP) (1346) Lead Styphnate (LSt) (1346)... 

Dinitromethylaniline (DNMA or DNMeAn), DNMA in Sulfuric Acid, Dinitrotoluene (DNT), Halite (EDNA), HMX (Cyclotetramethylene-cetranitramine), Lead Azide (LA), Lead Styphnate, Basic (LSt,B), Lead Styphnate, Normal (LSt,N), Mercury Fulminate (MF),... 

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

Soap, Mercury Fulminate Indicating. A soap contg triethanolamine and diphenylthiocarba-zone was patented for the removal of MF from skin surfaces. The soap is yellow in color, and changes tn rmrnle in the nresence of Ha salts Ref H.S. Mason I. Botvinik, USPublHealth-ServRept 5S, 1183-86 (1943) CA 37, 6482 (1943)... 

In early days Alfred Nobel already replaced mercury fulminate (MF, see above), which he had introduced into blasting caps, with the safer to handle primary explosives lead azide (LA) and lead styphnate (LS) (Fig. 1.17). However, the long-term use of LA and LS has caused considerable lead contamination in military training grounds which has stimulated world-wide activities in the search for replacements that are heavy-metal free. In 2006 Huynh und Hiskey published a paper proposing iron and copper complexes of the type [cat]2[Mn(NT)4(H20)2] ([cat]+ = NH4, Na+ M = Fe, Cu NT = 5-nitrotetrazolate) as environmentally friendly, green primary explosives (Fig. 1.17) [3]. 

The typical examples of priming mixtures used almost exclusively in the nineteenth century include mercury fulminate, potassium chlorate, antimony sulfide, glass powder, and gum Arabic. The priming mixtures widely used for small arms in the USA in the early 1900s were based on MF. The composition of the most typical one is summarized in Table 1.1. 

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... 

Mercury fulminate is also soluble in aqueous alkaline cyanides (e.g., KCN). The solubility depends on the concentration of cyanide solution (up to one-to-one ratio of MF to cyanide can be obtained) because the soluble double-salt Hg(CNO)2 KCN forms [15]. The MF in its white form can be precipitated back from this solution by addition of diluted nitric acid [3, 15, 57]. However, the purification of MF by recrystallization from cyanide solution is not effective, as the purity increases only slightly, e.g., from 98.39 to 98.60%. Boiling a cyanide... 

An alternative method of laboratory preparation of mercury fulminate is based on decomposition of the mercury salt of nitromethane published by Nef [14]. The mercuric salt is prepared in the first step of a reaction when mercuric chloride reacts with the sodium salt of nitromethane. The mercuric salt of nitromethane decomposes in a second step by boiling with dilute hydrochloric acid to produce MF [14] ... 

Unfortunately, the yield of MF is too low (only about 5 %) because the majority of the mercuric salt of nitromethane is converted into a basic mercury salt of formhydroxamic acid (also an explosive). This mercury salt cannot be converted into MF [2]. The nitromethane itself can also be converted into fulminic acid by nitrosation with nitrous acid to form nitroformaldehyde oxime. It further decomposes (by heating in water or nitric acid) to fulminic acid which is trapped with mercury nitrate as mercury fulminate [2]. 

It is further soluble in alkali cyanides, pyridine, and potassium iodide. Thiosulphate decomposes SF in a similar manner to that of mercury fulminate and may be used for nonexplosive decomposition of this substance. SF is insoluble in nitric add [28, 35]. Alike MF, silver fulminate reacts with concentrated hydrochloric acid. This... 

As opposed to alkaline azides which do not have properties of explosives, alkaline fulminates are mostly reported as highly sensitive and explosive substances [8,107, 108] even though one source mentioned sodium fulminate as not so sensitive (impact sensitivity for NaCNO to be 32 cm with 0.5 kg hammer compared to 7.5-10 cm MF under the same conditions) [27]. Sensitivity of these fulminates is reported as extreme and handling a hazardous operation [8, 107, 108]. Extreme sensitivity is further reported for the rubidium and cesium salts. Alkaline fulminates undergo explosion when initiated by flame, even in small amounts, whereas mercury fulminate only deflagrates. The exact sensitivity data are, however, not reported in this work [107]. Sensitivity of cadmium fulminate to impact is about the same as that of MF sensitivity of thallium fulminate is higher [15, 57]. 

The initiating efficiency is very high it surpasses mercury fulminate (several times) and even LA [48, 71, 88] (see Table 2.1). Taylor and Rinkenbach measured brisance of SA by the sand test [65]. They observed that brisance of SA is not that much greater than that to be expected for MF. Values for both primary explosives are summarized in Table 4.7. 

Lead picrate is considered highly sensitive to mechanical impact and thermal stimuli [6]. The anhydride is more sensitive to mechanical stimuli than the hydrates. Impact sensitivity of anhydride is significantly higher than the sensitivity of mercury fulminate (4 cm/0.5 kg vs. 24 cm for MF) [7,8]. Handling of lead picrate anhydride represents the same level of risk as handling of lead styphnate. The ignition temperature is 281 °C (explosion takes place instantaneously or within 1 s) [7]. The formation of lead picrate by reaction of tetryl (which decomposes to picric acid) with lead azide is reported as a possible reason for the higher sensitivity of this mixture compared to pure LA [6]. 

Brisance of DADP determined by the sand test is 30.1 g (0.4 g of peroxide initiated by 0.2 g mercury fulminate) which corresponds to 63 % TNT [17]. The initiation efficiency of DADP reported by Zhukov encyclopedia is between MF and LA [18]. This however disproved by Egorshev et al. [19] who tested DADP samples from 0.1 to 0.5 g pressed at 30 MPa with RDX as secondary charge in a blasting cap tube. Even 0.5 g DADP was not able to induce detonation of RDX, unlike TATP which caused full detonation of RDX in an amount of 0.1 g in the same conditions [19]. 

Friction sensitivity of silver acetylide-silver nitrate (both prepared from acidic and neutral solutions) is published lower than the sensitivity of mercury fulminate [21]. According to our experiments sensitivity of Ag2C2-AgN03 is between LA and MF (see Fig. 2.19) [23]. Silver acetylide-silver nitrate is exceptionally sensitive to flame. 

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