2. (Liebig.) A current of sulphuretted hydrogen gas is passed through water in which cyanate of silver is diffused, the process being suspended before all the cyanate of silver is decomposed.
Prop., &c. Cyanic acid is a limpid, colourless liquid; it reddens litmus; is sour to the taste; possesses a modified sulphurous odour, similar to that which is always perceived when any of its salts are decomposed by an acid; it forms salt with the bases called CYANATES; when in contact with water it suffers decomposition in a few hours, and is converted into bicarbonate of ammonia; it cannot be preserved for any time, as shortly after its preparation it spontaneously passes into a white, opaque, solid mass, to which the name CYAMELIDE has been given. By distillation this new substance is reconverted into cyanic acid.
CY′ANIDE. Syn. Cyan′uret; Cyan′idum, Cyanure′tum, L. The compound formed by the union of cyanogen with a metal or other radical. See Cyanogen, Hydrocyanic Acid, and the respective bases.
Cyanide, Al′kaline. Syn. Crude cyanide of potassium and sodium. Prep. (R. Wagner.) Dry ferrocyanide of potassium, 4 parts, dry carbonate of soda, 1 part, are melted together in an iron crucible at a red heat, and continually stirred until the iron rod comes out covered with a white crust, when the heat is withdrawn, and after a few moments’ repose the supernatant liquid portion is poured out on a clean iron slab. This crude mixed cyanide is quite as useful as the more expensive one of Liebig, and is equally fit for technical applications, as electrotyping, gilding, silvering, &c. See Potassium, Cyanide of.
CY′ANINE. A base discovered by Mr G. Williams in CHINOLINE BLUE. See below.
Cyanine, I′odide of. Syn. Chin′oline blue. The action of iodide of amyl upon chinoline gives rise to iodide of amylchinoline. Addition of excess of soda to an aqueous solution of this iodide produces a black resinous precipitate, which dissolves in alcohol with a magnificent blue colour. This precipitate is the IODIDE OF CYANINE, or CHINOLINE BLUE. Many attempts have been made to use it in dyeing; they have, however, failed on account of the instability of the colour.
CYAN′OGEN. CN or Cy. A highly important compound radical or quasi element, discovered by M. Gay Lussac in 1815.
Best obtained by carefully igniting dry cyanide of mercury in a small retort, and collecting the gas over mercury.
Prop., &c. A colourless gas, possessing a pungent and peculiar odour, resembling that of peach-kernels or prussic acid; under a pressure of about 4 atmospheres, at a temperature of 45°, it assumes the liquid form (Faraday), and this fluid again becomes gaseous on withdrawal of the pressure; water absorbs nearly 5 times its bulk of cyanogen at 60° Fahr., and alcohol about 23 times its volume; with hydrogen it forms hydrocyanic acid, and with the metals a most interesting and important class of bodies called cyanides or cyanurets; when kindled, it burns with a beautiful purple flame, carbonic acid and nitrogen being evolved. Sp gr. 1·806. See Hydrocyanic acid, &c.
Forms a bromide and iodide when the cyanide of mercury is distilled with bromine or iodine, and which are colourless, volatile, highly poisonous solids; and two isomeric chlorides, one a very volatile liquid, prepared by passing chlorine over moist cyanide of mercury, and the other in white volatile needles, prepared by exposing aqueous hydrocyanic acid to chlorine in sunshine.