|Jmol-3D images||Image 1|
|Molar mass||284.624 g/mol|
|Appearance||Grey, Pale Brown, or White Crystalline solid|
|Melting point||160 °C (320 °F; 433 K)|
|Boiling point||356.6 °C (673.9 °F; 629.8 K)|
|Solubility in water||slightly soluble|
|Solubility||soluble in ethanol, ammonia|
|Detonation velocity||4250 m/s|
|Main hazards||Highly Toxic, Shock Sensitive Explosive|
|Autoignition temperature||170 °C (338 °F; 443 K)|
|Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)|
|(what is: / ?)|
Mercury(II) fulminate, or Hg(CNO)2, is a primary explosive. It is highly sensitive to friction and shock and is mainly used as a trigger for other explosives in percussion caps and blasting caps. Mercury(II) cyanate, though its formula is identical, has a different atomic arrangement; the cyanate and fulminate anions are isomers.
First used as a priming composition in small copper caps after the 1830s, mercury fulminate quickly replaced flints as a means to ignite black powder charges in muzzle-loading firearms. Later, during the late 19th century and most of the 20th century, mercury fulminate or potassium chlorate became widely used in primers for self-contained rifle and pistol ammunition. Mercury fulminate has the distinct advantage over potassium chlorate of being non-corrosive, but it is known to weaken with time. Today, mercury fulminate has been replaced in primers by more efficient chemical substances. These are non-corrosive, less toxic and more stable over time; they include lead azide, lead styphnate and tetrazene derivatives. In addition, none of these compounds replacing Hg(II) fulminate requires mercury for manufacture, supplies of which can be unreliable in wartime.
Mercury(II) fulminate is prepared by dissolving mercury in nitric acid and adding ethanol to the solution. It was first prepared by Edward Charles Howard in 1800. The crystal structure of this compound was only determined in 2007.
Silver fulminate can be prepared in a similar way, but this salt is even more unstable than mercury fulminate; it can even explode under water and is impossible to accumulate in large amounts because it detonates under its own weight.
The thermal decomposition of mercury(II) fulminate can begin at temperatures as low as 100 °C, though it proceeds at a much higher rate with increasing temperature.
- 4 Hg(CNO)2 → 2 CO2 + N2 + HgO + 3 Hg(OCN)CN
- Hg(CNO)2 → 2 CO + N2 + Hg
- Hg(CNO)2 → :Hg(OCN)2 (cyanate or / and isocyanate)
- 2 Hg(CNO)2 → 2 CO2 + N2 + Hg + Hg(CN)2 (Mercury(II) cyanide)
In popular culture
- In the movie Mister Roberts (1955), Jack Lemmon's character Ensign Pulver uses fulminate of mercury to create a very large "firecracker".
- In the movie The Guns of Navarone (1961), David Niven's character Corporal Miller, suspecting sabotage, crushes and throws his "time pencils" consisting of "fulminate of mercury", "enough to blow off my hand. And very unstable, very delicate", to demonstrate that a traitor is in their midst.
- In the 2010 film The American, George Clooney's character uses fulminate of mercury to make explosive bullets for a fellow assassin.
- On AMC's Breaking Bad, in Season 1, Episode 6 "Crazy Handful of Nothin", Walter White enters Tuco Salamanca's hangout with a bag of fulminated mercury which he passes off as methamphetamine. When Tuco assumes that it is methamphetamine, Walt throws a piece to the ground, causing an explosion which damages the hangout. The effect was examined in an episode of MythBusters on 12 August 2013.
- In Burn Notice's season 4, episode 13 "Eyes Open" Michael Westen uses decoy mercury fulminate in order to distract a bomb man while Sam Axe searches his house.
- In the eighth episode of the anime Code Geass, the Japanese Liberation Front uses a mercury (II) fulminate cannon as an anti-Knightmare long range weapon.
- In Law & Order's season 7, episode 6 "Double Blind" the killer uses bullets tipped with fulminated mercury to kill a former school janitor.
- Edward Howard (1800). "On a New Fulminating Mercury". Philosophical Transactions of the Royal Society of London 90 (1): 204–238. doi:10.1098/rstl.1800.0012.
- W. Beck, J. Evers, M. Göbel, G. Oehlinger and T. M. Klapötke (2007). "The Crystal and Molecular Structure of Mercury Fulminate (Knallquecksilber)". Zeitschrift für anorganische und allgemeine Chemie 633 (9): 1417–1422. doi:10.1002/zaac.200700176.
- W. E. Garner & H. R. Hailes (1933). "Thermal decomposition and detonation of mercury fulminate". Proceedings of the Royal Society of London 139 (1–3): 1–40. Bibcode:1933CP....334..128S. doi:10.1098/rspa.1933.0040. Retrieved 2013-03-11.
|Wikimedia Commons has media related to Mercury(II) fulminate.|
- National Pollutant Inventory - Mercury and compounds Fact Sheet
- "300 years after discovery, structure of mercury fulminate finally determined". physorg.com. 24 August 2007.