Ammonium ferricyanide

Iron Blue, Cl Pigment Blue 27, which has been known by various names over the years, perhaps the best known being Prassian Blue, is ferric ammonium ferricyanide, FeNH Fe(CN)g(xH20. The hrst step in its preparation involves the precipitation of complex iron(ii) cyanides, e.g. potassium hexacyanoferrates(ii) with iron(i) salts, e.g. the sulfate or chloride, in an aqueous solution in the presence of ammonium... 

Ammonium ferricyanide, 2(NH4)3[Fe(CN)6].H20, may be prepared in a similar manner to the potassium salt (vide infra). It yields red monoclinic prisms, which readily dissolve m water. The solution hydrolyses upon standing, and is more sensitive to the action of light in this respect than is the potassium salt.3... 

Barium sodium ferricyanide, BaNaFe(CN)6.3H20, and Barium ammonium ferricyanide, BaNH4,Fe(CN)6.4H20, have also been prepared. 

Calcium ammonium ferricyanide, CaNH4.Fe(CN)6.3H20, and Calcium sodium ferricyanide, CaNa.Fe(CN)6.5H20, have also been obtained. 

Strontium potassium ferricyanide, SrKFe(CN)6.3H20 Strontium sodium ferricyanide, SrNaFe(CN)6.3H20 and Strontium ammonium ferricyanide, SrNH4Fe(CN)6.3H20 have also been prepared. 

C. ammonium hexacyanoferrate(lll) trihydrate (commonly called ammonium ferricyanide), (NH4)2Fe(CN)g 3H20 d. aluminum bromide hexahydrate... 

The most suitable oxidizing agent is potassium ferricyanide, but ferric chloride, hydrogen peroxide ia the presence of ferrous salts, ammonium persulfate, lead dioxide, lead tetraacetate or chromate, or silver and cupric salts may be useful. Water mixed, eg, with methanol, dimethylformamide, or glycol ethers, is employed as reaction medium. 

Feiri-. ferric, ferri-, iron(III). -acetat, n. ferric acetate, iron(IIl) acetate, -ammonsulfat, n. ammonium ferric sulfate, -bromid, n. ferric bromide, iron(III) bromide, -chlorid, n. ferric chloride, iron(lll) chloride, -chlor-wasserstoff, -chlorwasserstoffsMure, /. fer-richloric acid. -cyan, n. ferricyanogen. -cyaneisen, n. ferrous ferricyanide (Turn-bull s blue), -cyanid, n. ferric cyanide, iron(III) cyanide ferricyanide. 

Oxidation with ammonium persulfate and dilute caustic soda gives bismuth tetroxide, Bi204. The same product can be obtained by using other oxidizing agents such as potassium ferricyanide and concentrated caustic potash solution. 

Sydrosulphites may also be determined accurately by titration with standard ferricyanide 6 solution using ferrous ammonium sulphate as indicator the reaction is expressed by the equation ... 

The estimation of a vanadate solution by direct titration with ferrous sulphate or ferrous ammonium sulphate solution has been worked out, and is found to be specially applicable to the analysis of vanadium alloys. The vanadate is again reduced to tire tetravalent state by the ferrous salt, the end point being obtained by the use of potassium ferricyanide as internal indicator alternatively, a known excess of the ferrous salt solution is added to the vanadate, the amount unused... 

Emerson A 2% 4-aminoantipyrine solution in ethanol is sprayed on the plate, followed by an 8% aqueous potassium ferricyanide solution. The chromatogram is then placed in a chamber containing 25% ammonium hydroxide. 

The most common bleaching agents are copper sulfate, potassium permanganate, potassium ferricyanide, and potassium or ammonium dichromate. Most B R toners require a darker print than usual as there is often a loss of density. However, this is not always the case as copper bleaches will intensify the print. 

Distilled water at 125F/52C, 500.0ml Ferric ammonium citrate, 8.0g Potassium ferricyanide, 8.0 g Acetic acid, 28% solution, 265.0ml Distilled water to make 1.0 liter... 

Ammonium carbonate, saturated solution, 30.0ml Copper sulfate, 0.6g Potassium ferricyanide, 1.5 g... 

Experiment Prepare a solution of a ferrous salt by dissolving 2 grams of ferrous ammonium sulphate in 20 cc. of water, adding a little dilute sulphuric acid and a piece of iron wire. Test both this solution and a solution of a ferric salt (nitrate or chloride) with potassium ferrocyanide, potassium ferricyanide, and potassium sulphocyanate. Tabulate the results. These constitute the standard tests for ferrous and ferric salts. Write equation. 

A still more favourable effect upon current efficiency is achieved if certain substances such as fluorides are added, which raise the potential by some hundredths or even tenths of a volt. Other compounds such as chlorides, eyanides (potassium cyanide, ferrocyanide or ferricyanide) or thiocyanates have a double effect on one hand they decompose the Caro s acid and on the other hand they raise the anode potential. Ammonium thiocyanate is almost generally used. It reduces Caro s acid, at first, and changes it into sulphuric acid and hydrogen cyanide, the latter promoting a rise in the anode potential. 

The Ni and Pt complexes can also be incorporated into polymer films of quaternized poly(vinylpyridine) (PVP) and deposited onto the transparent electrode (84). Photocurrents are enhanced to microamps (pA), an increase that may be attributed to either the effect of immobilization of the complexes near the electrode surface or an increase of the excited-state lifetimes in the polymer matrix. However, the effective concentrations of the complexes in this study were much greater than for the acetonitrile solutions in their earlier work. The polymer films are not stable to continuous photolysis, and voltammograms of the films are quite sensitive to anions used in the supporting electrolyte. The system can be stabilized by using a polymer blend of PVP and a copolymer containing quaternary ammonium ion and including [Fe(CN)6]4- in the electrolyte solution (85). Upon irradiation of the visible MLCT bands of [M(mnt)2]2 (M = Ni, Pt), photocurrents are produced. The mechanism (Scheme 4) is believed to involve photooxidation of the metal bis(dithiolene) triplet state by the Sn02 electrode, followed by [Fe(CN)6]4 reduction of the monoanion, with completion of the ET cycle as ferricyanide, Fe(CN)6 3, diffuses to the other electrode and is reduced. 

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