Fulminates are chemical compounds which include the fulminate anion. The fulminate anion is a pseudohalic anion, acting like a halogen with its charge and reactivity. Due to the instability of the anion, they are friction-sensitive explosives. The best known is mercury fulminate which has been used as a primary explosive in detonators. Fulminates can be formed from metals, like silver and mercury, dissolved in nitric acid and reacted with alcohol. The chemical formula for the fulminate anion is O⁻N⁺C⁻. 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.{{cite journal
| title = On a New Fulminating Mercury.
| author = Edward Howard
| journal = Philosophical Transactions of the Royal Society of London
| year = 1800
| volume = 90
| issue = 1
| pages = 204-238
| url = http://links.jstor.org/sici?sici=0261-0523%281800%2990%3C204%3AOANFMB%3E2.0.CO%3B2-L
}}{{cite journal
| title = The Life and Work of Edward Charles Howard
| author = F. Kurzer
| journal = Annals of Science
| year = 1999
| volume = 56
| issue =
| pages = 113-141
| doi = 10.1080/000337999296445
}}. Their use in firearms in a fulminating powder was first demonstrated by a Scottish minister, A. J. Forsyth, in 1807. 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-NCO). 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{{cite book | first=Arthur
| last=Greenberg
| year=2000
| title=A Chemical History Tour
| publisher=John Wiley & Sons
| pages = 198-203
| id = ISBN 0-471-35408-2 }}.