Ferro-ferric oxide

Fig. 2.20 Ferrobacillus ferro-oxidans (NCIB 8 451), bacteria and encrustations of ferric oxides the proportion of bacteria was much increased by Filtering and centrifugation, x 260.

Ferri-ferrous Oxide or Magnetite, also known as Iron Oxide, Black or Ferro so-ferric Oxide, Feg04 mw 231 55, black cubic crysts or... 

In mixed solutions of ferro- and ferri-cytochrome c cross saturation effects could be observed by this technique. For example when the methyl resonance at +23.2 ppm of ferricytochrome c (Fig. 19) was irradiated, saturation effects were also observed in the methyl resonance of ferro-cytochrome c at +3.3 ppm (Fig. 27). This cross relaxation was shown to arise from an exchange of protein molecules, and hence also the saturated spins, between the ferrous and ferric oxidation states. The life-time in either oxidation state then has to be comparable to or shorter than the longitudinal spin relaxation time of the observed protons. Besides... 

Chemical properties of iron. Passivity. Ferrous compounds ferrous sulfate, ferrous ammonium sulfate, ferrous chloride, ferrous hydroxide, ferrous sulfide, ferrous carbonate. Ferric compounds ferric nitrate, ferric, sulfate, iron alum, ferric chloride, ferric hydroxide, ferric oxide (rouge, Venetian red). Potassium ferro-cyanide, potassium ferricyanide, Prussian blue. 

Ferro orange yellow. See Cadmium sulfide Ferropho HRS 2131 Ferrophos HRS 2132. See Di-iron phosphide Ferrosil 14. See Ferro-aluminum silicate Ferrosoferric oxide. See Iron oxide black Ferric oxide... 

White silver cyanide, thiocyanate, ferro- and yellow ferricyanide are decomposed with production of ignition-resistant silver. All metal ferro- and ferricyanides of the base metals leave a residue of ferric oxide and the particular metal oxide. For instance, the colorless ferrocyanides of zinc, cadmium, magnesium, calcium, barium, strontium, thorium etc. become yellow-brown Prussian blue and Turnbull s blue become dark (Fe304) and, later, brown (FegOg). Cupric ferricyanide (brown) and cupric ferrocyanide (violet-brown) are blackened when ignited because of the formation of cupric oxide. 

Limiting currents are usually associated with cathodic reactions (e.g., in metal deposition), although anodic reactions are by no means excluded. Whenever the supply of a dissolved species from the solution to the electrode surface becomes the rate-limiting factor, limiting-current phenomena may be observed. Anodic limiting currents can be obtained, for example, in the oxidation of ferrous to ferric ion, or ferro- to ferricyanide ion (El). Diffusion of H20 limits 02 evolution in fused NaOH (A2). In these examples the limiting current is caused by depletion of the reactant species at the anode. 

As an example of modeling a fluid in redox disequilibrium, we use an analysis, slightly simplified from Nordstrom et al. (1992), of a groundwater sampled near the Morro do Ferro ore district in Brazil (Table 7.2). There are three measures of oxidation state in the analysis the Eh value determined by platinum electrode, the dissolved oxygen content, and the distribution of iron between ferrous and ferric species. 

The sodium salt,1 NaFe(N0)2S203.2H20, is obtained in a similar manner to the preceding salt. It yields either laminated or needle-shaped crystals, which are glistening black in appearance. They are appreciably more soluble in water than those of the potassium salt, and yield a deep brown solution. The salt is fairly stable below 0° C., but above that temperature continuously evolves nitric oxide. When its aqueous solution is boiled, sulphur dioxide is expelled and ferric hydroxide precipitated. Upon concentrating the clear solution obtained by filtering, crystals of sodium ferro-heptanitroso sulphide, NaFe4(N0)7S3.H20, separate out.2... 

The results obtained at the cathode in the iodine coulometer show that Faraday s laws hold for the reduction of iodine to iodide ions the laws apply, in fact, to all types of electrolytic reduction occurring at the cathode, e.g., reduction of ferric to ferrous ions, ferricyanide to ferro-cyanide, quinone to hydroquinone, etc. The laws are applicable similarly to the reverse process of electrolytic oxidation at the anode. The equivalent weight in these cases is based, of course, on the nature of the oxidation-reduction process. 

The nickel in solution in the slurry is completely precipitated without liquids-solids separation with metallic powered iron at about 150°C under a pressure of 150 psig. The precipitated nickel contains occluded basic ferric sulfates which are decomposed by calcining at 950°C to produce a mixture of metallic nickel, metallic iron, and iron oxides. Melting of this mixture with a slag is calculated to yield a ferro-nickel containing more than 55% nickel. 

Solution. We see from the table that the ferrocyanide-ferricyanide potential is larger than the ferrous-ferric potential hence ferro-cyanide ion is a stronger reducing agent than ferrous ion, and ferricyanide ion is a w eaker oxidizing agent than ferric ion. 

Now let me come back to primary substitutions at the ferrocene nucleus. Together with Vil chevskaya, we phosphorylated ferrocene and its derivatives to triferrocenylphosphine oxides [263, 264). An unusual reaction, discovered in collaboration with Perevalova and Yur eva, was the direct cyanation of ferrocene with hydrocyanic acid in the presence of ferric chloride [265,272). Initially, cyanide attacks the iron atom of the ferricinium cation, then the cyanide group transfers to the ring while the iron is simultaneously reduced. The reaction was termed by us as the ricochet (from the metal to the nucleus) substitution it may be applied to many substituted ferrocenes and to the ruthenocenium cation [273), and it is now the simplest route to ferrocene carboxylic acids through their nitriles. Further, ferrocene was studied in acid-medium reactions with oxo compounds. With aldehydes [274), the reaction was complicated by the transformation of ferro-cenylalkyl carbinol formed Initially via the carbonium ion, followed by transformation to a radical which, in its turn, was coupled to 1,2-bis-(ferrocenylalkyl)ethane (27.5). The reaction with acetone led to 2,2-di-ferrocenylpropane (276). 

In the presence of an organism with iron-oxidizing ability such as T. ferro-oxidans, ferrous ions produced by the oxidation of a metallic sulfide can be re-oxidized to ferric ions and a cyclic mechanism established (eqn (11)) ... 

From the shape (rods) of the bacteria, they appear to be Acidithiobacillus ferro-oxidans but not Leptospirillum ferrooxidans. Finally, when the mixture of the mudstone and the medium for the sulfur-oxidizing bacteria (pH 6.5) supplemented with powdered pyrite is shaken in air, the pH of the culture medium is lowered over time. When the pH is lowered to below 4, the amount of ferrous ion plus ferric ion in the medium increases rapidly together with a parallel increase of sulfate ion (Yamanaka et al., 2002b). These phenomena are not observed with the mudstone heated at 121°C for 20 min. The results show that the acidophilic iron-oxidizing bacteria (growing at pH lower than about 4) oxidize pyrite but the usual sulfur-... 

Ferric trisulfate Ferri-Fioc. See Ferric sulfate Ferriheme hydroxide. See Hematin Ferrihexacyanoferrate. See Cl 77510 Ferriphosphate. See Ferric phosphate Ferriporphyrin hydroxide Ferriprotoporphyrin basic. See Hematin Ferrisulfate. See Ferric sulfate Ferrite yellow. See Iron oxide yellow Ferro BP-Kt, Ferro BP-91, Ferro CP-18, Ferro... 

Some ferro salts are delivered in bottles of uncoloured glass because oxidation of ferrous to ferric ion is inhibited by light. 

Although most complexes are named in the manner just outlined, some common, or trivial, names are still in use. Two such trivial names are ferro-cyanide for [Fe(CN)6] and ferricyanide for [Fe(CN)6] These common names suggest the oxidation state of the central metal ions through the 0 and i designations (0 for the ferrous ion, Fe " , in [Fe(CN)6] and i for the ferric ion, Fe, in [Fe(CN)6] ). These trivial names do not indicate that the metal ions have a coordination number of 6, however. The systematic names—hexacyanidoferrate(II) and hexacyanidoferrate(III)—are more informative. 

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