Prussian blues

The industrial production of Prussian blue is based on the reaction in aqueous solution of sodium hexacyanoferrate(n), Na4Fe(CN)6, with iron(n) sulfate, FeS04-7H20 in the presence of an ammonium salt, which results initially in the formation of the colourless insoluble iron(n) hexa-cyanoferrate(n) (Berlin white). Prussian blue is generated by subsequent oxidation with a dichromate or chlorate. 

Carbon blacks are manufactured from hydrocarbon feedstocks by partial combustion or thermal decomposition in the gas phase at high temperatures. World production is today dominated by a continuous furnace black process, which involves the treatment of viscous residual oil hydrocarbons that contain a high proportion of aromatics with a restricted amount of air at temperatures of 1400-1600 °C. 

Some examples of the applications of AC electrogravimetry to the study of the redox switching of inorganic and organic films are now reported. First, details about Prussian blue, where mainly cation movement can be detected, will be given. Then, the behaviom of PPY, where cations, anions and solvent participate in the charge compensation process, will be described. Finally, a system of sandwiched polymers will be analysed. 

Prussian blue can be obtained in different ways however, when Prussian blue films are produced galvanostatically following the pro- 

Prussian blue films can be reduced to the colourless form, called Everitt s salt (KFe4[Fe (CN)g]3 or K2FeFe (CN)g), or oxidized to the yellow form called Prussian yellow (Fe4[Fe (CNigJaCl or KFeFe (CNlgCl). These electrochemical processes can be easily detected by cyclic voltammetry of Prussian blue films in KCl solutions. The reduction process for the soluble Prussian blue structure has been described as  

The oxidation states concerned have since been confirmed by two different methods which identify the two species distinctly  

which confirms the charge transfer model and refutes the oscillation of valence concept because the charge states are stable for at least 10 s. The preparation of Turnbull s blue therefore involves a mutual redox reaction. 

Mossbauer studies also confirm the following reaction products [30]  

It can be seen that only in the case of the titanium(III)-ferricyanide couple is a mutual redox reaction observed. The spectrum of Fe3 [Co (CN)6]2 is also interesting in that the Fe + spectrum shows signs of two superimposed quadrupole doublets, one from the nitrogen-coordinated position, and the other from the interstitial sites. 

Application of pressure to insoluble Prussian blue causes considerable reversible reduction of high-spin ferric iron to high-spin ferrous iron [7]. 

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Ferric chloride solution is then added to com ert the sodium ferrocyanide to the deep blue ferric ferrocyanide (or Prussian Blue), dilute sulphuric acid being also added to dissolve any ferrous and ferric hydroxides present in the other-... 

It is essential to use an excess of sodium, otherwise if sulphur and nitrogen are both present sodium thiocyanate, NaCNS, may be produced in the test for nitrogen it may give a red coloration with ferric iron but no Prussian blue since there will be no free cyanide ions. With excess of sodium the thiocyanate, if formed, will be decomposed ... 

Upon boiling the alkaline ferrous salt solution, some ferric ions are inevitably produced by the action of the air upon the addition of dilute siilphurio acid, thus dissolving the ferrous and ferric hydroxides, the ferrocyanides reacts with the ferric salt producing ferric ferrocyanide (Prussian blue) ... 

Hydrochloric acid should not be used for acidifying the alkaline solution since the yellow colour, due to the ferric chloride formed, causes the Prussian blue to appear greenish. For the same reason, ferric chloride should not be added—as is frequently recommended a sufficient concentration of ferric ions is produced by atmospheric oxidation of the hot alkaline solution. The addition of a little dfiute potassium fluoride solution may be advantageous in assisting the formation of Prussian blue in a readily filterable form. 

If sulphur is present, a black precipitate of ferrous sulphide is obtained when the ferrous sulphate crystals dissolve. Boil the mixture for about 30 seconds, and acidify with dilute sulphuric acid the ferrous sulphide dissolves and a precipitate of Prussian blue forms if nitrogen is present. 

Nitrogen. Treat one portion with 1-2 ml. of 5 per cent, sodium hydroxide solution and 0 1 g. of powdered ferrous sidphate. Boil for 1 minute and cool. Cautiously acidify with dilute sulphuric acid (carbon dioxide is evolved). A precipitate of Prussian blue indicates that nitrogen is present. 

Prumngsas fuel Pruritis Pruritus Prussian blue Prussian Blue... 

Prussian Blue. Reaction of [Fe(CN)3] with an excess of aqueous h on(Ill) produces the finely divided, intensely blue precipitate Pmssian Blue [1403843-8] (tetrairon(Ill) tris(hexakiscyanoferrate)), Fe4[Fe(CN)3]. Pmssian Blue is identical to Turnbull s Blue, the name which originally was given to the material produced by reaction of [Fe(CN)3] with excess aqueous h on(Il). The soHd contains or has absorbed on its surface a large and variable number of water molecules, potassium ions (if present in the reaction), and h on(Ill) oxide. The h on(Il) centers are low spin and diamagnetic h on(Ill) centers are high spin. Variations of composition and properties result from variations in reaction conditions. Rapid precipitation in the presence of potassium ion affords a colloidal suspension of Pmssian Blue [25869-98-1] which has the approximate composition KFe[Fe(CN)3]. Pmssian Blue compounds are used as pigments in inks and paints and its formation on sensitized paper is utilized in the production of blueprints. 

The optimization of the biorecognition layer by the modification of a transducer used. Nanostmctured poly aniline composite comprising Prussian Blue or poly-ionic polymers has been synthesized and successfully used in the assembly of cholinesterase sensors. In comparison with non-modified sensors, this improved signal selectivity toward electrochemically active species and decreased the detection limits of Chloropyrifos-Methyl and Methyl-Pai athion down to 10 and 3 ppb, respectively. 

Sodium ferrocyanide (IOH2O) [13601-19-9] M 484.1, m 50-80 (ioses lOHjO), 435 (dec), d 1.46, pK 2.57, pK4 4.35 (for ferrocyanide). Crystd from hot water (0.7mL/g), until free of ferricyanide as shown by absence of Prussian Blue formation with ferrous sulfate soln. 

The CK" ion can act either as a monodentate or bidentate ligand. Because of the similarity of electron density at C and N it is not usually possible to decide from X-ray data whether C or N is the donor atom in monodentate complexes, but in those cases where the matter has been established by neutron diffraction C is always found to be the donor atom (as with CO). Very frequently CK acts as a bridging ligand - CN- as in AgCN, and AuCN (both of which are infinite linear chain polymers), and in Prussian-blue type compounds (p. 1094). The same tendency for a coordinated M CN group to form a further donor-aceeptor bond using the lone-pair of electrons on the N atom is illustrated by the mononuclear BF3 complexes... 

BerL Ber., abbrev. (Berliner Berichte) Berickte der deutscken chemiachen Gesellscka/t. Berliner-blau, n. Berlin blue, Prussian blue, -blaus ure, /. hydrocyanic acid, -braun, n. Prussian brown, -griin, n. Prussian green, -rot, n. Berlin red (a red lake color), -saure,/. prussic acid, -weiss, n. a kind of white lead. Bernstein, m. amber. — schwarzer —, jet. Bernstein-, amber succinic, succinyl, succino-. -alaun, m. aluminous amber, -aldehyd, n. succinaldehyde. bemateinartig, a. amber-like. 

Erkundigung, /. inqmry, erlangen, t.i. reach, obtain, attain, acquire. Erlanger-blau, n. Erlanger blue (a kind of Prussian blue), -leder, n. glove kid. 

Ferrifeiro-cyanid, n. ferric ferrocyanide (Prussian blue), -jodid, n. ferroeoferric iodide, -oxyd, n. ferroeoferric oxide, iron(II,III) oxide. 

Ferrocyan, n. ferrocyanogen. -eisen, n. ferric ferrocyanide (Prussian blue). 

Prussian blue, -bleiglas, n. potash lead glass. kAlibrleren, ]7.t. calibrate, groove (a roll). Kalibrierpipette,/. calibrating pipet(te). Ealibrierung,/. calibration. 

Milliarde, /. milliard (1,000 million, billion). milUonstel, a. millionth (part of), micro-. Miloriblau, n. milori blue (Prussian blue). 

Preussisch-blau, n. Prussian blue, -braim, n. Prussian brown. 

Sachsischblau, n. Saxon blue, smalt (sometimes) indigo a kind of Prussian blue, sacht, sachte, a. soft, gentle, light, smooth, easy (of silk) scoured. — adv. softly, gently, gradually. 

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