Cyanogen

[Gr. kyanos, and gennao, I produce.] (Chem.) C., or bicarb ide of nitrogen is one of the most interesting of the carbon compounds, its discovery by GayLu ac in 1814 having thrown considerable light upon two important facts in chemical science, - the existence of compounds acting as elements; and of substances having the same ultimate composition, but different properties. In fact, it was the means of originating new theories with respect to organic bodies generally. The name cyanogen, signifying blue- producer, was bestowed on this substance in consequence of its forming an e ential ingredient in Pru ian-blue. C. cannot be formed by the direct union of its elements, but may be obtained by pa ing nitrogen over a mixture of charcoal and carbonate of potash heated to redne in a porcelain tube. The potash becomes reduced to pota ium, carbonic oxide escapes, and C. is formed, which unites with the pota ium, yielding cyanide of pota ium. The reaction that takes place is interesting KO,CO2+C4+NK,NC2+3CO. The compounds of C. are, however, generally obtained from the ferrocyanide of pota ium, a salt formed by heating in a covered pot five parts of refuse animal matter, such as hide, hoof, and horn waste, with two parts of potash and iron filings. The ma , when cold, is digested in water, which di olves out the ferrocyanide of pota ium. Ten parts of this salt, distilled with 7 parts of oil of vitriol, and 5 or 6 parts of water, yield hydrocyanic or pru ic acid, which, if saturated with oxide of mercury, furnishes cyanide of mercury. This, on being dried and heated in a retort, furnishes C. It is a color guishable by the usual tests for that metal. The whole theory of cyanogen and its compounds is most intricate, and cannot be entered into here. Those who wish to pursue the subject further are referred to the discu ion of the properties of cyanogen, and its compounds, in the third volume of Miller's Elements of Chemistry. When binoxide of nitrogen is pa ed through a solution of hydro-ferrid cyanic acid, a decomposition takes place, an equivalent of hydrocyanic acid being replaced by an equivalent of binoxide of nitrogen. The compounds formed by this radical will be described under the head of NITRO-PRUSSIDES.-Equivalent, 26; sp . gr., 1-8064; combining value, 2. Form ., Cy. or C.N.