218 CYANOGEN COMPOUNDS. 



added ; is further formed, when a solution of sulpho- 

 carbamide is digested with silver oxide, lead oxide, or 

 mercury oxide on a water-bath. Transparent, thin 

 rhombic plates, pretty easily soluble in water and alco- 

 hol, sparingly soluble in ether. Fuses at 205, and 

 decomposes at a higher temperature. On the addition 

 of silver nitrate to its solution, long, colorless crystals, 

 C 2 H 3 AgE".HN0 3 , of a silken lustre, separate, from which 

 the nitric acid can be extracted by means of ammonia. 



When boiled with baryta water, dicyano-diamide 

 yields the barium salt of dicyan-amidic acid C 2 H 3 N 3 0, 

 together with cyanic acid and cyanamide. This acid 

 crystallizes in long lancet-shaped needles ; is monobasic. 

 Its potassium salt is also formed by the direct combi- 

 nation of cyanamide and potassium cyanate, when a 

 dry mixture of both bodies is heated to 60, or the 

 solution of the mixture allowed to stand for twenty- 

 four hours. 



"When a solution of dicyano-diamide in dilute acids 

 is evaporated, it is converted into a strongly alkaline 

 base dicyano-diamine, C 2 H 6 ]^ 4 0, water being assimilated. 

 It is easily soluble in water, but sparingly in alcohol. 

 Its salts, which crystallize well, remain behind on 

 evaporation, and from these it can be separated by 

 means of stronger bases. 



Cyanuramide (Melamine), C 3 H 6 lp = (CJST) 3 H 6 m 

 "When cyanamide is heated to 150, it is transformed 

 into this polymeric compound, the change being accom- 

 panied by a violent reaction. Large, shining, rhombic, 

 octahedral crystals; but slightly soluble in cold water, 

 more easily in hot water ; insoluble in ether and alco- 

 hol. Combines with acids, forming salts. When boiled 

 with hydrochloric acid, however, it is converted into 

 ammeline, C 3 H 5 N 5 (a white powder, insoluble in water), 

 which combines with nitric acid, forming a salt that 

 crystallizes well. 



Triethylmelamine, C 3 H 3 (C 2 H 5 ) 3 m Is produced, 

 when a solution of ethylsulphocarbamide is digested 

 with lead oxide or mercury oxide. Crystalline, easily 



