Cyanogen

“ Cyanogen and cyanogen compounds are extraordinarily powerful poisons. The minimum dose lies, as Lehmann has proved by experiments on animals, at about 0·05 per thousand of hydrocyanic acid in the atmosphere breathed; 1-5 mg. per kg. weight is fatal to animals; to man about 60 mg. would be fatal.
The poisonous action of cyanogen and cyanogen compounds depends upon their power of preventing absorption of oxygen from the blood by the tissues with the result that the venous blood flowing to the heart retains the bright red colour which otherwise only arterial blood exhibits. ”

“ Cyanogen, sī-an′o-jen, n. a compound of carbon, obtained by decomposing the cyanide of mercury by heat, so called from being an essential ingredient in the formation of Prussian blue.—n. Cy′anate, a salt of cyanic acid.—adj. Cyan′ic, of or belonging to cyanogen.—ns. Cy′anide, a direct compound of cyanogen with a metal ”

“ The ordinary yellow prussiate of potash has this constitution, and is called the ferro-cyanide.
CYANOGEN. A gaseous compound of two prime equivalents of charcoal = 12, and one of azote = 14 = 26; hydrogen being the radix or, 1. It consists of two volumes of vapour of carbon, and one volume of azote, condensed into one volume; and has therefore a density equal to the sum of the weights of these 3 gaseous volumes = 1·815. Cyanogen is readily procured by exposing the cyanide of mercury to a dull red heat in a retort; the gas is evolved and may be collected over mercury. ”

“ These crystals are the result of a combination of cyanogen and iodine. Nothing is easier than the preparation of iodide of cyanogen, a very volatile body, which possesses a strong tendency to assume a definite crystalline form. We pound in a mortar a mixture of 50 grams of cyanide of mercury, and 100 grams of iodine; under the action of the pestle the powder, which was at first a brownish colour, assumes a shade of bright vermilion red. The cyanogen combines with the iodine, and transforms itself into fumes with great rapidity. ”

“ Cyanogen, it may be mentioned, plays an important part in many organic reactions and compounds.
Gay-Lussac observed that the action of chlorine on hydrocyanic acid replaced the hydrogen forming cyanogen chloride, or acide chlorcyanique of his day; and he found that when beeswax was bleached by means of chlorine, it lost hydrogen and took up an equal volume of chlorine. At a royal ball at the Tuileries, in the reign of Charles X. (brother of Louis XVI.) , the guests were "much annoyed by the irritating vapours which came from the wax candles to illuminate the apartments." ”

“ Craig remarked keenly, still tasting, as he stood near the sun-parlor.
"Cyanogen?" I repeated.
"Yes, there are artificial aids to the senses that make them much keener than nature has done for us. For instance, if air contains the merest traces of the deadly cyanogen gas—prussic acid, you know—cigar smoke acquires a peculiar taste which furnishes an efficient alarm signal."
Dr. Leslie's face brightened as Kennedy proceeded. ”

“ Cyanogen chloride (CNCl) .—Cyanogen chloride is made from hydrocyanic acid or cyanide of mercury and chlorine. Cyanogen chloride itself is an extremely poisonous and irritating gas, and all the substances from which it is made are also poisonous. According to Albrecht cyanogen chloride can arise in the preparation of red prussiate of potash (by passage of chlorine gas into a solution of the yellow prussiate) if the solution is treated with chlorine in excess; the workers may thus be exposed to great danger. ”

“ If ammoniacal gas be formed, the hydrogen must proceed from decomposed water, and the azote from the nitric acid. Prussine, cyanogen, or carburet of nitrogen, the radical of prussic acid, may also be generated by the union of carbon and nitrogen or azote, in the same manner. We know that cyanogen may exist in the form of gas; but as it is inflammable, burning with a bluish flame mixed with purple, we may infer, nevertheless, that, if generated, it must undergo decomposition by the process of combustion. ”

“ Cyanogen is a substance which yielded on different occasions results of vaporous tension differing much from each other, though the substance appeared always to be pure. The following are numbers in which I place some confidence, the pressures being in atmospheres of 30 inches of mercury, and the marked results experimental. [16]
Ammonia.—This body may be obtained as a solid, white, translucent, crystalline substance, melting at the temperature of 103° below 0° ”

“ Animal matters always contain more carbon than is necessary for the formation of cyanogen by combining with the nitrogen also present. Consequently, when such substances are heated with pearlash, the excess of carbon reduces a portion of the carbonate to the metallic state, and this potassium combines with the cyanogen to produce potassium cyanide. The manufacture of yellow prussiate of potash may be conveniently divided into three stages: (1) The production of the molten mass technically known as “metal” ”

“ The real cause of this rapid decomposability of the plasm, and of the accompanying formation of carbonic acid, is found in the cyanogen, a remarkable body composed of an atom of carbon and an atom of nitrogen, which, in conjunction with potassium, forms the well-known and very virulent poison, cyanide of potassium. The non-nitrogenous decomposition-products of the dead and the living albumin agree in the main, but their nitrogenous products are totally different. ”

“ Thus, for instance, in the blast furnace a considerable quantity of cyanogen compounds are formed. This takes place because the nitrogen of the air blast comes into contact with incandescent carbon and various alkaline matters contained in the foreign matter of the ores. A considerable quantity of potassium cyanide is formed when wood charcoal is employed for iron smelting, as its ash is rich in potash. ”

“ Cyanic and cyanous acids are not poisonous, according to the experiments of Hünefield; [1893] but cyanogen is a powerful poison, as will be mentioned under the head of the Narcotic Gases.
The symptoms of hydrocyanic acid observed in man are very similar to those witnessed in animals. ”

“ All the cyanogen is more easily obtained in the form of potassium and sodium cyanide from potassium ferrocyanide by melting it with potash and adding metallic sodium.
The very poisonous hydrocyanic acid (prussic acid, HCN) is formed by the action of acids on potassium or sodium cyanide; small quantities indeed come off on mere exposure of these substances to the air. The increasing demand for potassium cyanide has led to experimental processes for producing it synthetically.
One method consists in the production of potassium cyanide from potash and carbon in a current of ammonia gas. ”

“ Add the suspected fluid solution of nitrate of silver; if hydrocyanic acid be present, a white cyanide of silver is formed, which is nearly insoluble in cold nitric acid, but is soluble in ammonia and cyanide of potash, and which, when heated to redness, gives off the inflammable violet-flamed cyanogen. ”

“ Following up analogies here, I would class cyanogen and sulphur together, and so I would their hydrides. HS, like cyanogen, is not strongly acid, indeed probably not acid at all, for as in the case of hydrocyanic acid HS exhibits a great tendency to oxidize when in contact with water and to form oxyacids, so that in testing this gas for acidity we are liable to obtain reactions not due to the gas itself. ”

“ Hydrocyanic or prussic acid, which consists of 1 atom of cyanogen = 26, + 1 of hydrogen = 1, is prepared by distilling the mercurial bi-cyanide in a glass retort with the saturating quantity of dilute muriatic acid. Prussic acid may also be obtained by precipitating the mercury by sulphuretted hydrogen gas from the solution of its cyanide; as also by distilling the ferrocyanide of potassium along with dilute sulphuric acid. Prussic acid is a very volatile light fluid, eminently poisonous, and is spontaneously decomposed by keeping, especially when somewhat concentrated. ”

“ Greene has no idea that this natural law is fatal to his artificial law of Avogadro and Ampere; "for," continues he, "the theory is fulfilled by the actual reaction." It is not. The theory requires two vols. of cyanogen and two vols. of chlorine, that is, the unit of numbers, to enter into reaction and to produce two vols. of the compound. But they produce four vols., and the non-condensation is therefore in opposition to the theory. It is true beyond doubt that the molecular weight of cyanogen chloride is contained in two volumes, in spite of the hypothesis, not on the ground of it ”

“ This may be accomplished by the use of toning baths of ferridcyanide or ferrocyanide, or other metal cyanogen salts, etc., or by either mixing the salts of other metals, as copper or iron, with the cyanic toning baths, or using them in the original solution, or by soaking the paper in them, as in Sella's process, previously to the application of the metal cyanic, mellonic or other toning baths. ”

“ The elements of cyanogen, combined with sulphur, form a salt radical, sulphocyanogen, C2NS2, which is expressed by the symbol Csy. The sulphocyanide of potassium, KCsy, is prepared by fusing ferrocyanide of potassium, deprived of its water of crystallization, intimately mixed with half its weight of sulphur and 17 parts of carbonate of potassa. The molten mass, after having cooled, is exhausted with water, the solution evaporated to dryness, and extracted with alcohol, from which the crystals of the salt are separated by evaporation. ”

“ Having never met this method of preparing cyanogen, experiments were made in the writer's laboratory to verify the statement. A blue, or what had the semblance of a blue color, could be obtained at the point given by Cutbush, but just as soon as the solution was acidulated, as is always done, the precipitate disappeared and there was not the slightest indication that Prussian blue had been formed. ”

“ Cyanogen is stable: not being resolved into its components below a bright red heat. Much less stable, however, are several of the oxides of nitrogen. Nitrous oxide, it is true, does not yield up its elements below a red heat; but nitrogen tetroxide cannot exist if water be added to it; nitrous acid is decomposed by water; and nitric acid not only readily parts with its oxygen to many metals, but when anhydrous, spontaneously decomposes. Here it will be well to note, as having a bearing on what is to follow, how characteristic of most nitrogenous compounds is this special instability. ”

“ In order to obtain the latter in an anhydrous form, the decomposition of heated mercury cyanide by hydrogen sulphide may be made use of. Here the sulphur and cyanogen change places, and hydrocyanic acid and mercury sulphide are formed: Hg (CN) 2 + H2S = 2HCN + HgS.
[45] A weak (up to 2 p.c.) aqueous solution of hydrocyanic acid is obtained by the distillation of certain vegetable substances. The so-called laurel water in particular enjoys considerable notoriety from its containing hydrocyanic acid. It is obtained by the steeping and distillation of laurel leaves. ”

“ The chemical elements involved are abundant; the physical conditions of temperature pressure and so forth at which living matter is most active, and within the limits of which it is confined, are familiar and almost constant in the world around us. On the other hand, it may be that the initial conditions for the synthesis of proteid are different from those under which proteid and living matter display their activities. E. Pflüger has argued that the analogies between living proteid and the compounds of cyanogen are so numerous that they suggest cyanogen as the starting-point of protoplasm. ”

“ Further, in regard to the question often raised as to the nature of certain of our elements, whether compound or not, it seems interesting that in this compound, cyanogen, we have a substance very similar to the element oxygen, one which at least only varies from it within the limits we are compelled to allow for variation in the members of certain well defined natural groups of our elements. We are thus, as far as is allowable from such apparent resemblances, justified in entertaining the supposition that oxygen itself is also a compound body. ”

“ The use of sugar-charcoal, may be perhaps an explanation of the weak formation of cyanogen, for in these numerous and successive chemical changes of matter, it is impossible to say how many sources of error may arise. The constant contradictions of each other, and the opposite statements made by chemists, of equal eminence, leave us in a wilderness of doubt, from which we are not likely to be freed, until definite laws shall be discovered to act as a guide in the comprehension of the higher branches of Chemical Philosophy. ”

“ Skey, for the purpose of ascertaining the value of cyanide of potassium as a preventive of the flouring of mercury iised for the extraction of gold, shows that cyanide of potassium does certainly prevent the sickening and flouring of mercury, or its tarnishing and granulation; but as cyanogen appears capable of dissolving metallic mercury, and is certain to be liberated from cyanide of potassium by carbonic acid, always present, it is questionable if cyanide of potassium could ever be profitably substituted for sodium as a preventive to the flouring of mercury. ”

“ In a similar manner, diamino derivatives are formed when cyanogen is condensed with ortho-diamines, and these amino compounds readily pass into the corresponding dioxy derivatives when acted upon with dilute hydrochloric acid. ”