Ferrates, hexacyano

Ferrates, aquapentachloro-stereochemistry, 50 Ferrates, hexacyano-history, 2... 

The existence of anode and cathode areas can be seen by the following experiment. A few drops of phenolphthalein are added to a solution of potassium hexacyanoferrate(III) and hydrochloric acid added, drop by drop, until the solution is colourless. (The phenolphthalein turns pink due to hydrolysis of the potassium hexacyano-ferrate(III).) Drops of this solution, about 1 cm in diameter, are now placed on a sheet of freshly abraded steel when pink cathode areas and blue anode areas appear. 

Potassium hexacyano-ferrate(II). K,Fe(CN)(, Potassium hexacyano-ferrateilll), K3Fe CN)6 Potassium thiocyanate. K.CNS... 

Heating with the following solids, their fusions, or vapours (a) oxides, peroxides, hydroxides, nitrates, nitrites, sulphides, cyanides, hexacyano-ferrate(III), and hexacyanoferrate(II) of the alkali and alkaline-earth metals (except oxides and hydroxides of calcium and strontium) (b) molten lead, silver, copper, zinc, bismuth, tin, or gold, or mixtures which form these metals upon reduction (c) phosphorus, arsenic, antimony, or silicon, or mixtures which form these elements upon reduction, particularly phosphates, arsenates,... 

To illustrate how the use of standard potentials may occasionally lead to erroneous conclusions, consider the hexacyanoferrate(II)-hexacyano-ferrate(III) and the iodide-iodine systems. The standard potentials are ... 

Meisel etal. [18-20] were the first to investigate how the addition of a polyelectrolyte affects photoinduced ET reactions. They found that charge separation was enhanced as a result of the retardation of the back ET when poly(vinyl sulfate) was added to an aqueous reaction system consisting of tris(2,2 -bipyridine)ruthenium(II) chloride (cationic photoactive chromophore) and neutral electron acceptors [21]. More recently, Sassoon and Rabani [22] observed that the addition of polybrene (a polycation) had a significant effect on separating the photoinduced ET products in an aqueous solution containing cir-dicyano-bis(2,2 -bipyridine)ruthenium(II) (photoactive donor) and potassium hexacyano-ferrate(III) (acceptor). These findings are ascribable to the electrostatic potential of the added polyelectrolytes. 

Aldehydes 2,4-Dinitrophenyl- hydrazine Formation of colored hydrazones or osazones. It is possible to distinguish between saturated and unsaturated hydrazones using potassium hexacyano-ferrate(III) [5]. [3,4]... 

See Copper(II) nitrate Ammonium hexacyanoferrate(II), or Potassium hexacyano-ferrate(II)... 

Caesium Chelation as copper hexacyano ferrate(II) on silica AAS - [864]... 

Caesium 137Cs adsorption on strong cation exchange resin ammonium hexacyano cobalt ferrate, dissolution in hydrochloric hydrofluoric acid /f counted for 137Cs lOpCi/1 [865]... 

Potassium hexacyano-ferrate(II). K4Fe(CN)6 Potassium hexacyano-ferrateflll), K, Fe(CN), Potassium thiocyanate, KCNS... 

The acidity constants for H4[Fe(C e] are pA i = 2.54, pA 2= 108, pAT3 = 2.65, pACj=4.19. Association constants have been published for alkali metal cations ion pairing with hexacyano-ferrate(II). ... 

The stabilization of Fe by 1,4,7-triathiacyclononane, ([9]-ane-S3, ttcn= (297), has permitted the preparation of the first authentic example of a Turnbull s Blue, i.e., an iron(II)-hexacyano-ferrate(lll) combination, in the form of [Fe(ttcn)2][Fe(CN)6] 2H20. This so-called Ukrainian Red, named in honor of the country of origin of several of the authors, is a valence-trapped (Robin and Day class compound. The redox potential for the [Fe(ttcn)2] " couple is... 

Potassium ferricyanide Ferrate (3-), hexacyano-, tripotassium (8) Ferrate (3-), hexakis(cyano-C)-, tripotassium. (OC-6-11)- (9) (13746-66-2)... 

Dipotassium sodium ferricyanide [dipotassium sodium hexacyano-ferrate(3-)] K2Na[Fe(CN)6] [31940-93-9]... 

The formal potential of the hexacyano-ferrate systems also shift by inserting different metal ions into the channels [57]. With the help of Born-Haber cycles, the following equation has been derived [55] ... 

To prepare metal hexacyanoferrate films, very frequently the following procedure was followed first a film of the respective metal, for example, cadmium [79], copper [80], silver [81], or nickel [82, 83] was elec-trochemically plated on the surface of a platinum electrode, and that was followed by chemical oxidation of the metal film in a solution of K3[Fe(CN)6], leading to the formation of the metal hexacyanoferrates. The same method has been used to produce films of nickel hexacyanoruthen-ate and hexacyanomanganate using the appropriate anions [83]. It is also possible to perform the oxidation of the deposited metals in solutions containing hexacyano-ferrate(II) by cyclic oxidation/reduction of the latter. In a similar way, films of copper heptacyanonitrosylferrate have been deposited [84]. 

A solid-state potassium-selective electrode based on potassium zinc hexacyano-ferrates, K2Zn3[Fe(CN)6]2, ion exchanger is described [472]. The sensor can be used in the determination of K+ ion in concentration range 10 — 1 M KCl. 

The electrodes modified by hexacyano-ferrates compounds were also used as voltammetric sensors [409-412]. The cadmium hexacyanoferrate-based composite ion-sensitive electrode for voltammetry was explored by Scholz and coworkers [409]. The potential of such electrode depends linearly on the logarithm of concentration of alkali and alkaline-earth metals ions in the solutions. Bo and fin have studied [410] Prussian blue (PB)/Pt modified electrode in GdGh electrolyte by cyclic voltammetry and in situ Fourier transform IR spectroscopy (FTIR) spectro-electrochemistry. Cadmium hexacyanofer-rates were formed on a PB film. 

There is no valid interpretation for the activation by OJ and by hexacyano-ferrate(III), although they fitted nicely in a reaction scheme with Cu(III) as the active species In the oxidation of an alcohol to an aldehyde Cu(III) would be reduced to Cu(I). In the subsequent reaction of Cu(I) with Oj, Cu(II)Oj was considered an intermediate yielding Cu(III) and H O. This intermediate would be in a reversible equilibrium with OJ and with the resting Cu(II)-enzyme. This resting enzyme would be oxidized by hexacyanoferrate(III) to the active Cu(III) species. There was unfortunately no indication in X-ray absorption measurements for the formation of Cu(III) with hexacyanoferrate(III) and the resting enzyme . EPR measurements indicated that Cu(II) was present in the active enzyme It was not possible, moreover, to detect Oj by the reduction of Fe(III)-cytochrome c in a galactose oxidase — galactose system... 

Modeling the biological oxidation of tertiary amines, Audeh and Lindsay-Smith239 prepared perhydropyrido[l,2-a]pyrimidine by the oxidative cyclization of 3-piperidino propylamine by use of potassium hexacyano-ferrate(III) in potassium hydroxide solution. 

Practical interest in high-molecular-weight poly (propylene oxide) centers in its potential use as an elastomer (19). Copolymerization of propylene oxide with allyl glycidyl ether gives a copolymer with double bonds suitable for sulfur vulcanization. Table IV shows the properties of elastomers made with a copolymer prepared with a zinc hexacyano-ferrate-acetone-zinc chloride complex. Also shown are the properties of elastomers made from partially crystalline copolymers prepared with zinc diethyl-water catalyst. Of particular interest are the lower room-... 

Cyanide ion, and hence nitrogen in the sample, may be detected by the Prussian Blue test. The filtered alkaline solution, resulting from the action of water upon the sodium fusion, is treated with iron(n) sulphate and thus forms sodium hexacyanoferrate(n). Upon boiling the alkaline iron(n) salt solution, some iron(m) ions are inevitably produced by the action of air upon addition of dilute sulphuric add, thus dissolving the iron(n) and (hi) hydroxides, the hexa-cyanoferrate(n) reacts with the iron(m) salt producing iron(m) hexacyano-ferrate(n), Prussian blue ... 

A. Eftekhari, Glycerol biosensor based on glycerol dehydrogenase incorporated into polyaniline modified aluminum electrode using hexacyano-ferrate as mediator, Sens. Actuators B Chem., 80(3) (2001) 283-289. 

R. Garjonyte and A. Malinauskas, Electrocatalytic reactions of hydrogen peroxide at carbon paste electrodes modified by some metal hexacyano-ferrates, Sens. Actuators B, 46 (1998) 236-241. 

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