NITROGEN COMPOUNDS 65 



Salts are formed from this acid by removing the H 

 of OH in the usual way, e.g. by the alkali metals. 

 The radical Nitroysl, NO, is also formed by removing 

 the OH, and the radical hydroximide by removing 

 the from nitrous acid. These radicals form many 

 organic compounds, as in the following equation, 

 where, however, the by-play of the radicals is not 

 represented. 



C 2 H 6 + HN0 2 - H 2 + C 2 H 5 N0 2 . 



That is to say ethyl-alcohol plus nitrous acid forms 

 ethyl-nitrite or sweet spirit of nitre and water. 



When nitrogen is pentavalent it may unite with 

 three atoms of oxygen, one of which is an OH, and 

 thereby form nitric acid, HN0 3 or N0 2 -OH. This 

 acid also forms many salts, as many metals are able 

 to replace the H in the molecule. Aromatic com- 

 pounds are also able to replace the H, and in this 

 manner the nitro-group assists in the formation of 

 various essences. The carbon atom can also unite 

 with the nitro-group, not merely by replacing the H 

 in the molecule, but by displacing the OH. 



As a triad, nitrogen combines with hydrogen to 

 form Ammonia, NH 3 , which is an exceedingly 

 important body in the organic world. Two or more 

 valencies of the N in NH 3 come into play when it is 

 approached by an electro-negative group, e.g. OH, 

 Cl, Br, I, acid radicals, etc. Thus NH 3 + 20H = 

 + NH 5 O or ammonium hydroxide. This body, 

 however, has not been isolated, any more than 

 ammonium, N 2 H 8 , which is admitted, on all hands 

 to exist, and probably consists of two NH 4 or 

 ammonium radicals joined. 



5 



