Mercury(II) fulminate, grey and white samples
| IUPAC name
| Other names
|Molar mass||284.624 g/mol|
|Melting point||160 °C (320 °F; 433 K) (explodes)|
|Boiling point||356.6 °C (673.9 °F; 629.8 K) (explodes)|
| 0.0704 g/cm3 (at 20 °C)|
0.1738 g/cm3 (at 49 °C)
|Solubility||Soluble in ammonia, ethanol|
|Solubility in chloroform||0.0066 g/cm3 (at 60 °C)|
|Solubility in diethyl ether||0.0028 g/cm3 (at 34 °C)|
|Safety data sheet||CPCB|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Mercury(II) fulminate, or simply mercury fulminate is a primary explosive, sensitive to friction and shock, widely used in the past as trigger for other explosives in percussion and blasting caps, now largely replaced by other less toxic, more stable and less corrosive primers, such as lead styphnate or tetrazene derivatives. It has the chemical formula Hg(CNO)2.
Although some sources identify mercury fulminate as mercury cyanate, this is incorrect, as fulminates have a direct metal-carbon bond, while cyanates have an ionic bond between metal and the oxygen from the cyanate group.
Mercury fulminate explodes when subjected to strong impact, friction, heat or electric arc, releasing a cloud of powdered mercury, nitrogen and carbon oxides.
- Hg(CNO)2 → Hg + 2 CO + N2
Mercury(II) fulminate is a grayish solid powder, insoluble in water, and slightly more soluble in organic solvents and ammonia.
Mercury(II) fulminate is a primary explosive material. It shows high sensitivity to shock, friction and heat, though unlike its silver counterpart, it's less sensitive and simply throwing a small bag of Hg(CNO)2 against a strong surface will not result in detonation. It has a detonation velocity of 4250 m/s.
Mercury(II) fulminate is not sold by any chemical supplier due to its hazards and has to be made.
Mercury fulminate can be prepared prepared by dissolving elemental mercury in nitric acid 70%, followed by the addition of ethanol to the solution. To make the resulting powder whiter, CuCl is used.
- Make blasting caps
Mercury(II) fulminate is sensitive to shock, friction and heat. Its decomposition products contain carbon dioxide/monoxide, nitrogen and mercury vapors, with the latter being extremely toxic.
Mercury fulminate is very toxic and ingestion may cause death.
Mercury(II) fulminate should only be stored for very short periods of time and used as soon as possible.
Addition of an acid, such as hydrochloric acid will convert it into mercury(II) chloride, which should be converted to an insoluble form, such as mercury sulfide and then taken to a hazardous chemical center for disposal.
DO NOT POUR IT DOWN THE DRAIN!