*cyanogen*

n. [ Gr. ky`anos a dark blue substance + -gen: cf. F. cyanogène. So called because it produced blue dyes. ] (Chem.) A colorless, inflammable, poisonous gas, C2N2, with a peach-blossom odor, so called from its tendency to form blue compounds; obtained by heating ammonium oxalate, mercuric cyanide, etc. It is obtained in combination, forming an alkaline cyanide when nitrogen or a nitrogenous compound is strongly ignited with carbon and soda or potash. It conducts itself like a member of the halogen group of elements, and shows a tendency to form complex compounds. The name is also applied to the univalent radical, CN (the half molecule of cyanogen proper), which was one of the first compound radicals recognized. [ 1913 Webster ]

☞ Cyanogen is found in the commercial substances, potassium cyanide, or prussiate of potash, yellow prussiate of potash, Prussian blue, Turnbull's blue, prussic acid, etc. [ 1913 Webster ]