Ferric ferrous oxide

Metal hydroxides in general are anion-selective in acid solution and turn to be cation-selective beyond a certain pH, called the point of the iso-selectivity, pHpjS it is pHpjS = 10.3 for ferric oxide and pHpis = 5.8 for ferric-ferrous oxide [72]. Adsorption of multivalent ions may also control the ion selectivity of hydrous metal oxides because of its effect on the fixed charge in the oxides. For instance, hydrous ferric oxide, which is anion-selective in neutral sodium chloride solution, turns to be cation-selective by the adsorption of such ions as divalent sulfate ions, divalent molybdate ions, and trivalent phosphate ions [70,73]. It is worth emphasizing that such an ion-selectivity change due to the adsorption of multivalent ions frequently plays a decisive role in the corrosion of metals. 

Let us consider a hydrous ferric-ferrous oxide layer, which is sensitive to the reduction-oxidation reaction on the surface of corroding metallic iron ... 

Ferrosoferric Oxide. Ferric ferrous oxide triiron tetraoxide black iron oxide magnetic iron oxide Ethiops iron. Fe204 mol wt 231.55. Fe 72.36%, O 27.64%. Occurs in nature as the mineral magnetite (red-black lumps). Prepn Gmelin s, Iron (8th ed) part B, 36-62 (1932) Ullmanns EncyklopSdie der Technischen Chemie vol. 6, 420 (1955). Review Robl, ngew. Chem. 70, 367 (1958). 

FEP FEP resin. See Fluorinated ethylene/propylene Ferric ferrous oxide. See Iron oxide black Ferric octoate. See Iron octoate... 

Synonyms Black magnetic oxide Black oxide, precipitated Black rouge Cl 77499 Ethiops iron Ferric ferrous oxide Ferrosoferric oxide Iron oxide Iron (II, III) oxide Iron (III) oxide Iron (II) oxide, black Iron (II, III) oxide, black Iron oxide magnetic Iron oxides (FesOJ Magnetite Pigment black 11 Triiron tetraoxide Classification Syn. iron oxide Empirical FejO,... 

Iron Titanates. Ferrous metatitanate [12168-52-4] FeTiO, mp ca 1470°C, density 472(0), an opaque black soHd having a metallic luster, occurs in nature as the mineral ilmenite. This ore is used extensively as a feedstock for the manufacture of titanium dioxide pigments. Artificial ilmenite may be made by heating a mixture of ferrous oxide and titanium oxide for several hours at 1200°C or by reducing a titanium dioxide/ferric oxide mixture at 450°C. 

Ferrous orthotitanate [12160-20-2] Fe2Ti04, is orthorhombic and opaque. It has been prepared by heating a mixture of ferrous oxide and titanium dioxide. Ferrous dititanate [12160-10-0] FeTi20, is orthorhombic and has been prepared by reducing ilmenite with carbon at 1000°C. The metallic ion formed in the reaction is removed, leaving a composition that is essentially the dititanate. Ferric titanate [1310-39-0] (pseudobrookite), Fe2TiO, is orthorhombic and occurs to a limited state in nature. It has been prepared by heating a mixture of ferric oxide and titanium dioxide in a sealed quartz tube at 1000°C. 

Higher and lower oxides are distinguiahed as -oxyd and -oxydvl Eisenoxyd, ferric oxide Eisenoxydul, ferrous oxide) or by Latin forms (Ferrioxyd, ferric oxide Ferrooxyd, ferrous oxide). 

The structure of millscale consists of three superimposed layers of iron oxides in progressively higher states of oxidation from the metal side outwards, viz. ferrous oxide (FeO) on the inside, magnetite (Fe304) in the middle and ferric oxide (Fe203) on the outside. The relative portions of the three oxides vary with the rolling temperatures. A typical millscale on 9.5 mm mild steel plate would be about 50/tm thick, and contain approximately 70% FeO, 20% Fej04 and 10% FejOj. 

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. 

In accord with this mechanism, free peroxyl radical of the reaction product hydroperoxide activates the inactive ferrous form of enzyme (Reaction (1)). Then, active ferric enzyme oxidizes substrate to form a bound substrate radical, which reacts with dioxygen (Reaction (4)). The bound peroxyl radical may again oxidize ferrous enzyme, completing redox cycling, or dissociate and abstract a hydrogen atom from substrate (Reaction (6)). 

Figure S-4S shows the polarization curves observed, as a function of the film thickness, for the anodic and cathodic transfer reactions of redox electrons of hydrated ferric/ferrous cyano-complex particles on metallic tin electrodes that are covered with an anodic tin oxide film of various thicknesses. The anodic oxide film of Sn02 is an n-type semiconductor with a band gap of 3.7 eV this film usually contains a donor concentration of 1x10" ° to lxl0 °cm °. For the film thicknesses less than 2.5 nm, the redox electron transfer occurs directly between the redox particles and the electrode metal the Tafel constant, a, is close to 0.5 both in the anodic and in the cathodic curves, indicating that the film-covered tin electrode behaves as a metallic tin electrode with the electron transfer current decreasing with increasing film thickness.

Iron s two oxide compounds (ferrous(II) oxide—FeO) and (ferric(III) oxide—Fe O ) are the third and seventh most abundant compounds found in the Earth s crust. 

Mononuclear octahedral/trigonal bipyramidal iron centers are found in either the ferric or the ferrous oxidation state (Whittaker etal., 1984 Arciero et ai, 1983). Because the iron may participate directly in catalysis as either a Lewis acid or base, only one state is the active form for a given enzyme. Transient redox changes may occur during turnover, but the enzyme returns to its initial condition. In contrast the tetrahedral mononuclear iron proteins appear to function primarily as electron transfer agents and therefore change oxidation state with a single turnover. 

HELP HEU HFO HFR HLW HREE HRL HT HTGR HWR Hydrological evaluation of landfill performance Highly enriched uranium Hydrous ferrous oxide or ferric hydroxide Hot fractured-rock High-level nuclear waste Heavy rare earth elements (Gd-Lu) Hard rock laboratory High temperature High-temperature gas-cooled reactor Heavy water reactor... 

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

Ferrous Oxide (Iron Monoxide), FeO mw 71.85, blk pdr, sp gt 5-7, mp 1420° insol in w, sol in acids. Can be prepd by heating ferrous oxalate under the hood, while avoiding inhalation of toxic CO evolved. Some ferric oxide is present as impurity. Used as ingredient of some expls... 

Figure 17. Proposed phase relations where K is a mobile component and Al, Fe are immobile components at about 20°C and several atmosphere water pressure for aluminous and ferric-ferrous mica-smectite minerals. Symbols are as follows I illite G = non-expanding glauconite Ox = iron oxide Kaol = kaolinlte Mo montmorillonite smectite N nontronitic smectite MLAL aluminous illite-smectite interlayered minerals Mlpe = iron-rich glauconite mica-smectite interlayered mineral. Dashed lines 1, 2, and 3 indicate the path three different starting materials might take during the process of glauconitization. The process involves increase of potassium content and the attainment of an iron-rich octahedral layer in a mica structure.

Ferric potassium sulfate 1 A156—A157 Ferric triazide see Ferric azide 1 AS43 Ferricyanides 6 F15 Ferri-ferrous oxide 6 FI 5 Ferrifracteur 6 Fi5 Ferrite 6 FI 5... 

Iron Vanadate is, metallurgically, the most important vanadate. Precipitation of a solution of a vanadate with ferrous sulphate gives rise to a precipitate of indefinite composition, ortlio-, pyro-, meta-, and perhaps a poly-vanadate being present, as well as ferric or ferrous oxide. Reduction of the vanadate to a vanadyl salt may also ensue. The precipitate is usually colloidal and carries down with it some sodium vanadate. The dried powder may be either green, yellow, brown, or red the more nearly the precipitate approximates to a red colour the lower is its vanadium content. An iron vanadate has also been prepared by electrolysis of a solution of sodium vanadate between iron poles.1... 

In redox electrodes an inert metal conductor acts as a source or sink for electrons. The components of the half-reaction are the two oxidation states of a constituent of the electrolytic phase. Examples of this type of system include the ferric/ferrous electrode where the active components are cations, the ferricyanide/ferrocyanide electrode where they are anionic complexes, the hydrogen electrode, the chlorine electrode, etc. In the gaseous electrodes equilibrium exists between electrons in the metal, ions in solution and dissolved gas molecules. For the half-reaction... 

It remains to be noted that, when there is no method available for ascertaining the formula weight or a compound, the simplest formula, based on chemical analysis and the use of symbol weighLs of the contained elements, is used, e g., ferric oxide, FejOj, ferroferric oxide, FejCXt, ferrous oxide, FeO, cupric oxide (black copper oxide), CuO. cuprous oxide (red copper oxide). CujO. The customary formula of water is H2O. which is correct ai temperatures above I00°C—actually, liquid water is mainly dihydrol (HjOh. 

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