CYANOGEN COMPOUNDS. 211 



existence, but is probably the vapor of the liquid 

 variety. 



Solid cyanogen chloride, (CN~) 3 C1 3 , is formed 

 from anhydrous cyanhydric acid and chlorine, in the 

 direct light of the sun ; and by conducting chlorine in 

 a solution of 1 part of mercury cyanide and 4 parts of 

 ether; is also formed by distilling cyanuric acid with 

 phosphorus chloride. Shining needles or laminae, 

 which fuse at 145, and boil at 190. But slightly 

 soluble in cold water, easily in alcohol and ether. 

 Decomposed by boiling with water or alkalies into 

 cyanuric acid and hydrochloric acid. It suffers the 

 same decomposition even at the ordinary temperature, 

 when its solution in dilute alcohol is allowed to stand. 



Cyanogen bromide, CKBr,and Cyanogen iodide, 

 GNT, are formed by heating potassium or mercury 

 cyanide with bromine or iodine. They are crystal- 

 lizing compounds, easily volatile, soluble in water and 

 alcohol. Cyanogen . bromide, when heated alone or 

 with anhydrous ether to 130-140, is converted into 

 a polymeric compound (CT) 3 Br 3 . This body forms a 

 white, amorphous powder, fusing above 300, which is 

 decomposed by boiling with water and even in contact 

 with moist air, yielding cyanuric and hydrobromic 

 acids. 



Cyanic Add. 

 CKOH. 



Formation. The cyanates of the alkalies are pro- 

 duced by heating metallic cyanides in the air or in 

 contact with easily reducible metallic oxides. Cyanic 

 acid cannot be separated from these salts, inasmuch as 

 it breaks up with water, the moment it becomes free, 

 forming carbonic acid and ammonia. The free acid 

 can only be obtained by the dry distillation of cyanuric 

 acid, or by heating urea with phosphoric anhydride. 



Properties. Colorless liquid, of a penetrating, pun- 

 gent, acid smell. Only stable below 0. Removed 

 from the freezing mixture, it becomes turbid, and is 



