Mercury(II) fulminate
From Wikipedia, the free encyclopedia
| Mercury(II) fulminate | |
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| Identifiers | |
| CAS number | 628-86-4 |
| PubChem | |
| Properties | |
| Molecular formula | Hg(CNO)2 |
| Molar mass | 284.624 g/mol |
| Appearance | Grey Crystalline solid |
| Density | 4.43 g/cm3 |
| Explosive data | |
| Shock sensitivity | High |
| Friction sensitivity | High |
| Explosive velocity | 4250 m/s |
| Hazards | |
| Autoignition temperature |
150 °C |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox references |
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Mercury(II) fulminate, Hg(CNO)2, is a primary explosive. It is highly sensitive to friction and shock. It 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 and/or potassium chlorate became widely used in primers for rifle and pistol ammunition. Mercury fulminate has the distinct advantage over potassium chlorate, being non-corrosive, but it is known to weaken with time. Today, mercury fulminate has been replaced in primers by more efficient chemical substances. Those are non-corrosive, less toxic and more stable over time: lead azide, lead styphnate and tetrazene derivatives.
[edit] Preparation
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.[1] The crystal structure of this compound was only determined in 2007.[2]
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.
[edit] References
- ^ Edward Howard (1800). "On a New Fulminating Mercury". Philosophical Transactions of the Royal Society of London 90 (1): 204–238. doi:.
- ^ 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:.
