Fulminate

${\displaystyle {\ce {^{-}\!C{\equiv }{\overset {+}{N}}-O^{-}}}}$ Structural formula of the fulminate ion

Fulminates are chemical compounds which include the fulminate ion. The fulminate ion, CNO−
is a pseudohalic ion, acting like a halogen with its charge and reactivity. Due to the instability of the ion, fulminate salts are friction-sensitive explosives. The best known is mercury(II) fulminate, which has been used as a primary explosive in detonators. Fulminates can be formed from metals, such as silver and mercury, dissolved in nitric acid and reacted with ethanol. It is largely the presence of the weak single nitrogen-oxygen bond which leads to its instability. Nitrogen very easily forms a stable triple bond to another nitrogen atom, forming gaseous nitrogen.

Historical notes

Fulminates were discovered by Edward Charles Howard in 1800.^[1][2][3] The use of fulminates for firearms was first demonstrated by a Scottish minister, A. J. Forsyth, who patented his scent-bottle lock in 1807; this was a small container filled with fulminate of mercury.^[4][5] Joshua Shaw then made the transition to their use in metallic encapsulations, to form a percussion cap, but did not patent his invention until 1822.

In the 1820s, the organic chemist Justus Liebig discovered silver fulminate (Ag-CNO) and Friedrich Wöhler discovered silver cyanate (Ag-OCN). The fact that these substances have the same chemical composition led to an acrid dispute, which was not resolved until Jöns Jakob Berzelius came up with the concept of isomers.^[6]

Compounds

• Fulminic acid
• Mercury(II) fulminate
• Potassium fulminate
• Silver fulminate

See also

English pronunciation of the word "fulminate"

• The cyanate (-OCN) and isocyanate (-NCO) groups have a related structure.
• The nitrile (-CN) and isonitrile (-NC) groups.
• The functional group fulminate (-ONC) corresponds to the fulminate ion; if the organic bond is at the other end, we get instead the nitrile oxide (-CNO) functional group.
• Internal ballistics

References

1. Edward Howard (1991). "On a New Fulminating Mercury". Philosophical Transactions of the Royal Society of London. 90 (1): 204–238. doi:10.1098/rstl.1800.0012.
2. F. Kurzer (1999). "The Life and Work of Edward Charles Howard". Annals of Science. 56 (2): 113–141. doi:10.1080/000337999296445.
3. "Edward Charles Howard (1774-1816), Scientist and sugar refiner". National Portrait Gallery. 2005-01-05. Retrieved 2006-08-30.
4. Alexander Forsyth in Encyclopædia Britannica
5. "Rifled Breech Loader". Globalsecurity.org.
6. Greenberg, Arthur (2000). A Chemical History Tour. John Wiley & Sons. pp. 198–203. ISBN 0-471-35408-2.