FUNDAMENTAL CONCEPTIONS 205 



as well as its salts must belong to the isocyanogen compounds and 

 consequently must contain bivalent carbon. An exhaustive study 

 of prussic acid and the cyanides establishes this sharply, especially in 

 the case of the salts, from a chemical standpoint. The relation of 

 fulminic acid to prussic acid corroborates the evidence. 



You are all familiar with fulminate of mercury a substance which 

 is made on a commercial scale and used for explosives. It was dis- 

 covered in 1800 by Howard, and analyzed in 1824 by Liebig in Gay 

 Lussac's laboratory. We obtain it by dissolving mercury in concen- 

 trated nitric acid and adding the resulting solution to ordinary 

 alcohol. It has the empyrical formula HgC 2 N 2 O 2 , and being obtained 

 from ethylalcohol, CH 3 CH 2 OH, fulminic acid was supposed to 

 have two carbon atoms in its molecule, H 2 C 2 N 2 2 . The constitution 

 of this substance was for a long time a great puzzle to chemists. That 

 we have here a substance very closely related to prussic acid was dis- 

 covered by accident. In working with the mercury salt of isonitro- 

 methane it was found that this compound is spontaneously converted 

 at into fulminate of mercury according to the equation, 



O H 



H C = NOh -H / C = NO* 1 ^ 11 ' + C : NOh S- 



HO 



This synthesis led directly to the conclusion that fulminate of 

 mercury possesses a constitution entirely analogous to cyanide of 

 mercury, C = Nhg, i. e., that it contains the isocyanogen radical with 

 bivalent carbon. A further study of the fulminates established this 

 point with precision. Especially striking is the behavior of fulminates 

 towards dilute acids. Liebig and Gay Lussac state in 1824, judging 

 from the odor, that fulminate of silver gives prussic acid with dilute 

 hydrochloric acid. A more careful study of this reaction in 1894 

 proved that not a trace of prussic acid but a substance formylchloride 



H 



oxime, C = NOH, is formed which possesses the following re- 



Cl 



markable properties. Long needles, clear as glass, which decompose 

 and explode at 20 ; extremely volatile even at and having an odor 

 similar to prussic acid which is obviously due to a partial dissociation 

 into fulminic acid. Aqueous silver nitrate converts it quantitatively 

 into chloride and fulminate of silver, 



H 



^ C = NOH + 2AgNO 3 ->AgON = C + AgCl + 2HNO 3 . 

 Cl 



