Ferrocyanide compounds

Metal colorants such as copper sulfate, ferricyanide, and ferrocyanide compounds can be irritating or highly toxic. If a colorant reacts with the metal, irritating acid fumes can be released. 

Applying colorants to metals should be done in a well-ventilated room. Copper sulfate can release irritating sulfur dioxide, and ferricyanide or ferrocyanide compounds with acid and/or heat will release hydrogen cyanide gas. Needless to say, these combinations should not be used to color metal. 

Adsorbents have been widely used to collect dissolved Cs in both fresh and seawater. Ferrocyanide compounds are known as specific adsorbents for cesium (Krylov et al., 1973 Folsom et al., 1975 Mann and Casso, 1984) and are used in two forms, granular or impregnated on fiber. Milham and Kantelo (1984) used a granular form of potassium cobalt ferrocyanide (KCFC) to collect Cs in the Savan-... 

Ferrocyanide compounds Polyvinylpolypyrrolidone Silica gel/silicon dioxide (colloidal)... 

The use of black cyanide as a fumigant and rodenticide makes use of the atmospheric humidity action that Hberates hydrogen cyanide gas. It can only be used effectively ia confined spaces where hydrogen cyanide builds up to lethal concentrations for the particular appHcation. Black cyanide is also used ia limited quantities ia the production of pmssiates or ferrocyanides (see Iron compounds). 

Nitric oxide is the simplest thermally stable odd-electron molecule known and, accordingly, its electronic structure and reaction chemistry have been very extensively studied. The compound is an intermediate in the production of nitric acid and is prepared industrially by the catalytic oxidation of ammonia (p. 466). On the laboratory scale it can be synthesized from aqueous solution by the mild reduction of acidified nitrites with iodide or ferrocyanide or by the disproportionation of nitrous acid in the presence of dilute sulfuric acid ... 

Cyaneisen, n. iron cyanide, -kalium, n. potassium ferrocyanide, -verbindungt /. iron cyanogen compound, specif, a ferrocyanide. 

Other solutions to dealing with interferences in the detection of H O have included the use of a copperfll) diethyldithiocarbamate precolumn to oxidize the sample before it reaches the immobilized enzyme, as well as the use of a palladium/gold sputtered electrode which catalyzes the oxidation of hydrogen peroxide In addition, peroxidase has been used to catalyze the reaction between hydrogen peroxide and iodide ferrocyanide and organo-fluorine compounds Am-... 

Unfortunately, many compounds contain bonds that are a mixture of ionic and covalent. In such a case, a formal charge as written is unlikely to represent the actual number of charges gained or lost. For example, the complex ferrocyanide anion [Fe(CN)6]4- is prepared from aqueous Fe2+, but the central iron atom in the complex definitely does not bear a +2 charge (in fact, the charge is likely to be nearer +1.5). Therefore, we employ the concept of oxidation number. Oxidation numbers are cited with Roman numbers, so the oxidation number of the iron atom in the ferrocyanide complex is +11. The IUPAC name for the complex requires the oxidation number we call it hexacyanoferrate (II). 

Fig. 4. Visible spectra of catalase, compound I, and compound II 5 [xM (heme) beef liver catalase (Boehringer-Mannheim) in 0.1 M potassium phosphate buffer pH 7.4, 30°C. Compound I was formed by addition of a slight excess of peroxoacetic acid. Compound II was formed from peroxoacetic acid compound I by addition of a small excess of potassium ferrocyanide. Absorbance values are converted to extinction coefficients using 120 mM for the coefficient at 405 nm for the ferric enzyme (confirmed by alkaline pyridine hemochromogen formation). Spectra are corrected to 100% from occupancies of f 90% compound I, 10% ferric enzyme (steady state compound I) and 88% compound II, 12% compound I (steady state compound II). The extinction coefficients for the 500 to 720 nm range have been multiplied by 10. Unpublished experiments (P.N., 1999).

Iron in both the +2 and +3 valence states forms several stable hexacoordi-nated octahedral complexes with cyanide (CN ) ion, known as ferrocyanide or hexakiscyanoferrate(4—), [Fe(CN)6] and ferricyanide or hexakiscyanofer-rate(3-), [Fe(CN)6]3-, respectively. The simple iron(II) cyanide, Fe(CN)2 is unstable and all iron cyanide compounds known are coordination complexes. 

Potassium ferrocyanide, K4[Fe(CN)6] 3H20 occurs as a trihydrate. The compound is a spin-paired diamagnetic complex in which the ferrocyanide anion constitutes the Fe2+ ion, octahedrally coordinated with six CN ions. It is a yellow monoclinic crystaUine sohd density 1.85 g/cm decomposes at 60°C and soluble in water but insoluble in alcohol and ether. 

Hexacyanoferric(II) acid, ferrocyanic acid or tetrahydrogen hexakis(cyanate-(4-)) [17126-47-5] is used to prepare many adducts with oxygen-containing organics. Also addition compounds with inorganic salts are known. This acid may be obtained as a white precipitate upon addition of potassium ferrocyanide to concentrated hydrochloric acid ... 

Several types of corrosion inhibitors have been investigated in the last 20 years [53-55] these include calcium and sodium nitrites, sodium benzoate, sodium/potassium chromate, sodium salts of silicates and phosphates, stannous chloride, hydrazine hydrate, sodium fluorophosphate, permanganate, aniline and related compounds, alkalis, azides, ferrocyanide, EDTA and many chelating compounds. However, in terms of field practice and research data, nitrite-based compounds occupy a dominant position. 

More complex salts are also known belonging to the series. For instance, if a solution of nitro-pentammino-cobaltic chloride be treated with an aqueous solution of sodium cobaltic nitrite, Na3Co(N02)6, a yellowish-brown crystalline precipitate of nitro-pentammino-cobaltic cobalti-nitrite, [Co(NH3)5(N02)]3[Co(N02)6]2, is formed. Also the corresponding ferrocyanicle may be prepared by treating nitro-pentammino-salts with potassium ferrocyanide. The compound obtained is a reddish-yellow substance of composition [Co(NH3)5(NO,)], [Fe(CN )6].6H20. 

Second-Order Rate Constants for the Oxidation of Ferrocenes and Ferrocyanide by Compounds I (k6) and II (k7) and for the HRP-Catalyzed Steady-State Oxidation ( ) at [H202] 2.4 x 1 4 M (pH 6, 25 °C)... 

Uses Of the Stassfurt salts.—The magnesium compounds in the Stassfurt salts are used for the preparation of magnesium and of its salts. The potash salts are an essential constituent of many fertilizers used in agriculture, etc. 22 and potassium chloride is the starting-point for the manufacture of the many different kinds of potassium salts used in commerce—carbonate, hydroxide, nitrate, chlorate, chromate, alum, ferrocyanide, cyanide, iodide, bromide, etc. Chlorine and bromine are extracted by electrolysis and other processes from the mother liquids obtained in the purification of the potash salts. Boric acid and borax are prepared from boracite. Caesium and rubidium are recovered from the crude carnallite and sylvite. 

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