Cyanogen

Cyanogen (Gk. kuanos, blue), CN, a gas which may be prepared by heating the cyanide of gold, silver, or mercury. It has a pungent smell, is poisonous, and burns with a purplish flame. It may be condensed by cold (21° C), a pressure (21 atms.) to a colourless liquid of sp. gr. 0.866. It is soluble in water, but the solution soon decomposes. It is found, to a small extent, in blast furnace gases. In its chemical relations cyanogen shows many analogies to chlorine and the halogens. The single group, or "radical," CN, enters into the composition of many compounds, playing the part of an element, and the investigations of cyanogen and its derivatives, by Gay Lussac, formed one of the main foundations of the "radical theory" (q.v.).