Iron hydrate

The hydration of the ferrite phase (C AF) is of greatest interest in mixtures containing lime and other cement compounds because of the strong tendency to form soHd solutions. When the sulfate in solution is very low, soHd solutions are formed between the cubic C AH and analogous iron hydrate C FHg. In the presence of water and siUca, soHd solutions such as C3 ASH4-C3FSH4 may be formed (33). Table 7 Hsts some of the important phases formed in the hydration of mixtures of pure compounds. 

The possible content of hydrated alumina and iron. Hydrated alumina minerals like gibbsite [14762-49-3] Al(OH)2, boehmite [1318-23-6] AlOOH, and diaspore [14457-84-2] AlOOH, occur ia bauxitic clays. Bauxites grade chemically iato hydrated fermgiaous and manganiferous laterites. Hence, finely divided M2O2, usually hydrated, may be a significant constituent of a clay where M may be A1 or Fe. Hydrated colloidal s ica may play a role ia the sHppery and sticky properties of certain clays. 

Oxydul, n. (lower or-ous) oxide, (formerly) protoxide. -eisen, n. ferrous iron, -hydrat, n. hydrated -ous oxide (-ous hydroxide), oxydullsch, a. of lower valence, -ous, Oxydul-oxyd, n. an oxide in which the metal has a lower and a higher valence, oso-ic oxide, mixed oxide. -salz, n. lower or -ous salt. 

Water is usually involved in corrosion. Consider the corrosion of iron. Hydrated iron(III) oxide, or rust, forms by the following overall reaction ... 

More recently, the concentration of Tc in coastal seawater samples collected 1993 in Fukuoka (Kyushu) Japan was determined by ICP-MS. Tc was enriched by coprecipitation on iron hydrated oxide and separated from impurities by solvent extraction and ion exchange techniques. The Tc concentrations found were only 1-7, uBql. The activity ratio of Tc/ - Cs was 2.7 10", which is very close to the value expected for fallout from nuclear tests [79]. 

Iron gluconate dihydrate Iron (II) gluconate dihydrate. See Ferrous gluconate dihydrate Iron hemiphosphide. See Di-iron phosphide Iron (III) hexacyanoferrate (4). See Cl 77510 Iron hydrate Iron hydroxide (INCI). See Iron (III) oxide hydrated... 

Hydrated ferric oxide Iron hydrate Iron hydroxide (INCI) Iron hydroxide oxide Iron oxide hydrated... 

Johnson (1994) investigated the performance of different DFT methods. With materials important to the geosciences, Xantheas (1995) and Simon et al. (1999) have compared methods on water clusters, Harris et al. (1997) on iron hydrates, and Bacelo and Ishikawa (1998) on sodium hydrates. Gas phase acidities were investigated by Smith and Radom (1995). Recently, Bak et al. (2000) compared the accuracy in reaction enthalpies and atomization energies of different small systems using several methods and basis sets. 

Figure 13.3 schematizes reactions (13.17 and 13.18) for iron in water. Iron hydrates into Fe " ions and free electrons e while oxygen O2 is reduced by electrons and reacts with water forming OH ions, according to Eq. (13.18). OH ions, in turn, allow iron reduction that precipitates as Fe(OH)2 or Fe(OH)3 (rust). The iron hydroxide Fe(OH)2 that forms from reaction (4) in Eq. (13.17), in fact, precipitates because it is insoluble in water solution or is further oxidized into ferric hydroxide Fe(OH)3 that gives rust that characteristic reddish color, through the reaction... 

The data in Tables 4.2 and 4.3 refer to ions in aqueous acid solution for cations, this means effectively [MlHjO), ]" species. However, we have already seen that the hydrated cations of elements such as aluminium or iron undergo hydrolysis when the pH is increased (p. 46). We may then assume (correctly), that the redox potential of the system... 

Many salt-like halides can be prepared by the action of the hydro-halic acid. HX, on the metal or its oxide, hydroxide or carbonate. The halides prepared by this method are often hydrated, particularly when a less electropositive metal is involved, for example zinc, iron. 

Ironilll) chloride is a black, essentially covalent solid, in which each iron atom is surrounded octahedrally by six chlorine atoms. It is prepared by direct combination of iron with chlorine or by dehydration of the hydrated chloride, by one of the methods given on p.343). 

This is the most important reaction of iron from an economic point of view essentially, rusting is the formation of hydrated iron(III) oxide in the presence of oxygen and water. The process is essentialh... 

Nickel forms a green hydrated sulphate NiS04. TH O and the double sulphate (NH4),S04. NiS04.6HtO (cf. iron, p. 396). 

Hydrated iron(III) fluoride [15469-38-2] is easily prepared from yeHow Fe202 and hydrofluoric acid. Dehydration of FeF 3H20 produces... 

Acetates. Anhydrous iron(II) acetate [3094-87-9J, Ee(C2H202)2, can be prepared by dissolving iron scraps or turnings in anhydrous acetic acid ( 2% acetic anhydride) under an inert atmosphere. It is a colorless compound that can be recrystaUized from water to afford hydrated species. Iron(II) acetate is used in the preparation of dark shades of inks (qv) and dyes and is used as a mordant in dyeing (see Dyes and dye intermediates). An iron acetate salt [2140-52-5] that is a mixture of indefinite proportions of iron(II) and iron(III) can be obtained by concentration of the black Hquors obtained by dissolution of scrap iron in acetic acid. It is used as a catalyst of acetylation and carbonylation reactions. 

Iron(III) ammonium citrate [1185-57-5] is of indefinite stoichiometry. A brown hydrated compound [1332-98-5] of iron(III) ammonium citrate contains 16.5—18.5% iron, - 9% ammonia, and 65% citric acid. A green hydrated compound [1333-00-2] contains 14.5—16% iron, 1% ammonia, and 75% citric acid. Iron ammonium citrates are water soluble but are insoluble in alcohol. The compounds are used to fortify bread, milk, and other foods (see... 

Halides. AH of the anhydrous and hydrated binary haUdes of iron(Il) and iron(Ill) are known with the exception of the hydrated iodide of iron(Ill). A large number of complex iron haUdes have been prepared and characterized (6). 

Iron(III) fluoride ttihydrate [15469-38-2] FeF3-3H2 0, crystallizes from 40% HF solution ia two possible crystalline forms. At low temperature the a-form, which is isostmctural with a-AlF 3H2O, is favored. High temperatures favor P-FeF 3H2O, the stmcture of which consists of fluoride-bridged octahedra with one water of hydration per unit cell. 

Iron(II) bromide [7789-46-0] FeBr2, can be prepared by reaction of iron and bromine ia a flow system at 200°C and purified by sublimation ia oitrogea or uader vacuum. Other preparative routes iaclude the reactioa of Fe202 with HBr ia a flow system at 200—350°C, reactioa of iroa with HBr ia methanol, and dehydration of hydrated forms. FeBr2 crystallizes ia a layered lattice of the Cdfy type and has a magnetic moment of... 

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