Mercury(II) fulminate

Mercury(II) fulminate (Hg(ONC)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; cyanate and fulminate are isomers.

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Today mercury fulminate tends to be replaced by other primary explosives which are less toxic and more stable over time: lead azide, lead styphnate and tetrazene derivatives.

Used in percussion caps, this compound quickly replaced flints as a means to ignite a black powder charge in a firearm.

Preparation

It 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]

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.  

References

• 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.

1. ^ Edward Howard (1800). "On a New Fulminating Mercury.". Philosophical Transactions of the Royal Society of London 90 (1): 204-238.