Fulminates are chemical compounds which include the fulminate ion (CNO−, C−≡N+−O−). The fulminate ion is a pseudohalic ion because its charge and reactivity are similar to those of the halogens. 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. The weak single nitrogen-oxygen bond is responsible for their instability. Nitrogen very easily forms a stable triple bond to another nitrogen atom, forming nitrogen gas.
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, Alexander John Forsyth, who patented his scent-bottle lock in 1807; this was a small container filled with fulminate of mercury.[4][5] Joshua Shaw determined how to encapsulate them in metal to form a percussion cap, but did not patent his invention until 1822.
The functional group fulminate (-ONC) corresponds to the fulminate ion; if the organic bond is at the other end, the nitrile oxide (-CNO) functional group is obtained instead.