When cyanogen is prepared by heating mercuric cyanide, a residue known as para-cyanogen, (CN)x, is left; this is to be regarded as a polymer of cyanogen.
The next salt to be obtained was the mercuric salt, which was prepared in 1 799 by Edward Charles Howard, who substituted mercury for silver in Brugnatelli's process.
von Liebig (1823), who heated a mixture of alcohol, nitric acid and mercuric nitrate; the salt is largely manufactured by processes closely resembling the last.
A laboratory method is to mix solutions of sodium nitromethane, CH 2: NO(ONa), and mercuric chloride, a yellow basic salt being formed at the same time.
The use of mercuric fulminate as a detonator dates from about 1814, when the explosive cap was invented.