Iron Prussian blues

Table 5 Compositions and iron oxidation states in cobalt-iron Prussian Blue analogues Na cCo Fe(CN)6-zH20. ...

Cyanide of iron—Prussian blue—may be judged of by the following —... 

It is intriguing to note that the colours of green KMn(CN)3 and tan K sMn(CN)3 are the reverse of what one might expect from parallels in the iron Prussian blue system KFe(CN)3 or Fe Fe CN) ] is colourless, whereas K jFefCN or KFe [FeIII(CN)6] is deep blue because of an interoxidation-state electron-transfer band. Clearly, further detailed study of these manganese systems is required, and the final explanation will probably need to take account of the availability of the MnIV state—note especially the tendency, under some conditions, for [Mn "(CN)6]3- to disproportionate to Mn11 and Mniv. 

State. When both iron environments contain only iron(II), the resulting salt is not colored (Prussian White). The oxidation state localization in PB has been studied extensively. Structures, electrochemical behavior (electrodes batteries), and uses in medicine (treatment of Cs and of thallium poisoning) of Prussian Blue are mentioned in a review of cyanide complexes. In cobalt-iron Prussian Blue analogues, NaxCo3,Fe(CN)6-zH20 electronic and spin states are controlled by temperature and the ligand field strength around the Co + ions, which in turn is determined by the Co Fe ratio. ... 

NOTE.—The blue substance formed at times in this preparation is probably produced as the result of the following cause Commercial potassium cyanate may contain potassium ferrocyanide. If this is the case, when a solution of the salt is evaporated in the air with ammonium sulphate containing a trace of iron, Prussian blue is formed. 

Ferric ferrocyanide 4 167 Fe4(Fe(CN)6)3 Berlin Blue Ferrocyanlde of iron ferrocyanuret of iron ferroprusslate of Iron percyanide of Iron Prussian blue sesqu I ferrocyanide of iron. 

Liu, H., Matsuda, K., Gu, Z., Takahashi, K., Cui, A., Nakajima, R., et al. (2003). Reversible valence tautomerism induced by a single-shot laser pulse in a cobalt-iron Prussian blue analog. Physical Review Letters, 90, 167403. 

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 ... 

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

Potassium iron hexacyanoferrate —see Prussian blue Potassium peroxodicarbonate... 

FIGURE 16.16 When potassium cyanide is added to a solution of iron(ll) sulfate, the cyanide ions replace the H.O ligands of the [Fe(H20), - + complex (left and produce a new complex, the hexacyanoferrate(ll) ion, Fe(CN)(l 4 (right). The blue color is due to the polymeric compound called Prussian blue, which forms from the cyanoferrate ion. 

Some of the iron(III) ions in the reagent arc converted to iron(II) ions by reducing substances and then react to produce Prussian blue or Hjrnbull s blue. 

Prussian blue (iron hexaferrocyanate) came into contact with ethylene oxide at 20 C. The reaction was very violent and the residue formed combusted spontaneously in air. 

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. 

Zboril R, Machala L, Mashlan M, Sharma V (2004) Iron(III) oxide nanoparticles in the thermally induced oxidative decomposition of prussian blue, Fe4[Fe(CN)6]3. Cryst Growth Design 4(6) 1317-1325... 

Prussian blue (PB ferric ferrocyanide, or iron(III) hexacyanoferrate(II)) was first made by Diesbach in Berlin in 1704.88 It is extensively used as a pigment in the formulation of paints, lacquers, and printing inks.89,90 Since the first report91 in 1978 of the electrochemistry of PB films, numerous studies concerning the electrochemistry of PB and related analogs have been made,92 with proposed applications in electrochromism1 and electrochemical sensing and catalysis 93... 

The fact that Prussian blue is indeed ferric ferrocyanide (Fe4in[Fen(CN)6]3) with iron(III) atom coordinated to nitrogen and iron(II) atom coordinated to carbon has been established by spectroscopic investigations [4], Prussian blue can be synthesized chemically by the mixing of ferric (ferrous) and hexacyanoferrate ions with different oxidation state of iron atoms either Fe3+ + [Fen(CN)6]4 or Fe2+ + [Fem(CN)6]3. After mixing, an immediate formation of the dark blue colloid is observed. However, the mixed solutions of ferric (ferrous) and hexacyanoferrate ions with the same oxidation state of iron atoms are apparently stable. 

Hove, K., H. Staaland, O. Pedersen, and H.D. Sletten. 1990b. Effect of Prussian blue (ammonium-iron-hexacyanoferrate) in reducing the accumulation of radiocesium in reindeer. Rangifer, Spec. Iss. No. 3 43. 

---