l6 CYANAMID — MANUFACTURE, CHEMISTRY AND USES 



Nitrogen in solution 



As cyanamide As dicyanamide 



After Per cent. Per cent. 



I day 14.56 0,70 



3 days 11.76 1.54 



6 days 9.10 2.84 



II days 5.18 2.24 



18 days > 1.75 1. 71 



31 days 0.00 1.25 



45 days 0.00 0.84 



58 days 0.00 0.53 



76 days 0.00 0.23 



Basic calcium cyanamide is formed in solutions containing 

 an excess of lime: 



N N 



/// /// 



Cv + Ca(OH), ^ Cv /CaOH 



\NCa \N< 



\CaOH 



It can be obtained from lime-nitrogen by extracting with a 

 small portion of water, filtering, and allowing the solution to 

 stand several hours. Long, needle-shaped white to trans- 

 parent crystals separate out on the walls of the vessel. Filter 

 with suction in the absence of carbon dioxide (under a bell- 

 jar). Dry under a bell-jar over caustic potash. 



This salt is almost insoluble in water. In the dry condition 

 it is stable at ordinary temperatures, but when heated to 

 120° C. it rapidly decomposes to dicyandiamide and calcium 

 hydroxide. 



Calcium cyanamide carbonate^ is readily formed by the 

 action of carbon dioxide on calcium cyanamide in the presence 

 of moisture. It can be prepared by extracting lime-nitrogen 

 with one and one-half times its weight of water, filtering and 

 bubbling CO2 through the filtrate. In about half an hour a 

 white precipitate forms, which can be filtered and washed with 

 alcohol or ether. 

 ^ Ulpiani, loc cit. 



