Silver ferrocyanide

Ferrocyan-kaUum, n. potassium ferrocyanide. -kupfer, n. cupric ferrocyanide. -natrium, n. sodium ferrocyanide. -silber, n. silver ferrocyanide. -verbindung, /. ferrocyanide. -wasserstoff, m., -wasserstoffsMure, /. ferro-cyanic acid, -zink, n. zinc ferrocyanide. -zinn, n. tin ferrocyanide. 

The first reported isonitrile complex was synthesized by the alkylation of silver ferrocyanide with ethyl iodide (7) ... 

Each of the two latter graphical formulas as written above assumes that the iron and hydrogen are attached directly to the nitrogen and not to the carbon atoms. This is supported, in so far as the hydrogen atoms are concerned, by Freund s 6 preparation of ethyl ferrocyanide from silver ferrocyanide and ethyl iodide —... 

Silver ferrocyanide, Ag4Fe(CN)6, is obtained as a white precipitate by double decomposition of a silver salt with potassium ferrocyanide. With nitric acid it yields orange-red silver ferricyamde.6... 

AgCl -i- K4[Fe(CN) J Ag4[Fe(CN)e] + 4 KCl This reaction cannot be detected by mere observation because both silver salts are white. If, however, a precipitate of silver chloride that has been treated with K4Fe(CN)e is moistened with a drop of concentrated nitric acid, the silver ferrocyanide is converted into silver ferricyanide, and the color changes from white to red-brown ... 

The nature Of the ions.—In 1814, G. F. Parrst12 found that in the electrolysis of aq. soln. of potassium ferrocyanide the alkali accumulated about the negative pole, and ferric oxide and hydrocyanic acid about the positive pole, and the work of J. F. Daniell and W. A. Miller, and of W. Hittorf (1859), showed that double salts are of two kinds, and that in the one kind the metal is bound as a complex negative ion, and in the other it is the positive ion. For example, in the electrolysis of potassium silver cyanide, KCy.AgCy, W. Hittorf (1859) found that silver was deposited on the cathode, whereas with salts of the type AgN03 it is deposited on the anode. Hence, it was inferred that the salt ionizes KAgCy2=K,- -AgCy2 similarly,... 

Chlorides. — Deflagrate a mixture of 0.5 gm. of powdered potassium ferrocyanide and 1 gm. of potassium nitrate, by introducing small quantities at a time into a porcelain crucible heated to redness. Treat the residue with 20 cc. of water, filter, and to the filtrate add 3 cc. of nitric acid and silver nitrate solution. The liquid should not develop more than a slight opalescence. 

Hydrogen nitroso ferricyanide or nitroprussic acid, H2[Fe(CN)5NOJ, is obtained by decomposition of the silver salt with hydrochloric acid or by the action of dilute sulphuric acid upon the barium salt. It is also formed when nitric oxide is bubbled through an acidified solution of potassium ferrocyanide.4 The reaction proceeds in two stages, namely, (a) oxidation to the ferricyanide, and (b) substitution of the cyanogen radicle by NO —... 

Silver carbonyl ferrocyanide, Ag3[Fe(CN)5CO], is obtained as a white curdy precipitate on addition of the potassium salt to silver nitrate solution in the presence of acetic acid.4 It rapidly darkens even when protected from the light. Insoluble in boiling acetic acid, it is slightly soluble in dilute mineral acids evolving hydrogen cyanide. Potassium hydroxide liberates silver oxide, potassium carbonyl ferrocyanide being simultaneously produced. 

Uses cyanide salts are used in silver and gold mining—the cyanide process sodium cyanide is extensively used in industries for electroplating calcium cyanide is used as a fumigant potassium silver cyanide is used in silver plating potassium ferrocyanide is used to achieve a blue color on cast bronze sculptures... 

Some of these complexes are very stable—the stability of the ar-gentocyanide ion, Ag((JN)2"", for example, is so great that addition of sulfide does not cause silvef sulfide to precipitate, even though the solubility product of silver sulfide is very small. The ferrocyanide ion,... 

A micromethod has been described for organic sulfur determination by an amplification reaction involving barium bromate and sulfuric acid. If amplification reactions are carried out in a chromatographic column, phosphate, ferrocyanide, chromate, zinc, iron, and silver can be amplified directly or indirectly. ... 

The dihydroxide crystallises in hair-fine, white needles, and is isolated by boiling the bromide with silver oxide in 80 per cent, alcohol for twenty hours. Treatment of the hydi oxide in 50 per cent, alcohol with sulphuric acid precipitates the siilj hute as microscopic white needles, suddenly blackening above 150 C. The dibrornide with silver nitrate gives tlie dinitrate, from which the dichloride is prepared. It crystallises in white needles, >Lpt. C. The following compounds are also mentioned oxalate, succinate, ferrocyanide, white precipitates, and the azelate, w hite scales. 

Copper ferrocyanide silicate Lead silicate Peptone tannate Barium sulphate Silver chloride... 

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