CYAN'OGEN (Gk. K fwvoc, kyanos, dark blue vns, genes, producing, from 717 vecrOcu, gignesthai, Lat. gignere, Skt. jun, to be born). An important compound of carbon and nitrogen obtained by heating dry cyanide of mercury in bard glass tubes. It is a poisonous gas, 11:1\111g a peculiar odor and dissolving quite readily in water and in alcohol. If ignited in air it burns with a purple flame. its carbon combining with the oxygen of the air to form carbon dioxide, while its nitrogen is set free. When dry, eyan ogen is an exceedingly stable rubstanee and may be heated as high as 800° C. without being de composed: in aqueous solution, however, it grad ually undergoes a series of chemical changes resulting in the formation of ammonia, hydro cyanic aeid, urea, oxalic aeid, nail other com pounds. The molecular formula of eyanogen is its molecule being composed of two 'cyan ogen groups' (CN, or, as it is often written, Cy), which enter into the composition of a large number of other substances known. Some of
these interesting substances having a blue color, the name cyanogen has been applied to the gas from which they are derived; but that gas itself is perfectly colorless. During the preparation of eyanogcn from the cyanide of mercury, an amorphous brown substance forms, which has the same percentage composition as cyanogen, but probably a much higher molecular weight; this compound is called paracyunoricn and is denoted by the symbol Paracyanogen may be readily transformed into cyanogen gas by heating.
The derivatives of cyanogen form a large group of compounds, including hydrocyanic acid and its salts, the ferro-cyanides and ferri-cyan ides, cyanic and eyanurie acids and their deriva tives, etc. The most important of these com pounds are described in special articles.