Hydrolysis of iron

Iron(III) hydroxide [1309-33-7], FeH02, is a red-brown amorphous material that forms when a strong base is added to a solution of an iron(III) salt. It is also known as hydrated iron(III) oxide. The fully hydrated Fe(OH)3 has not been isolated. The density of the material varies between 3.4-3.9 g/cm, depending on its extent of hydration. It is insoluble in water and alcohol, but redissolves in acid. Iron(III) hydroxide loses water to form Fe203. Iron(III) hydroxide is used as an absorbent in chemical processes, as a pigment, and in abrasives. Salt-free iron(III) hydroxide can be obtained by hydrolysis of iron(III) alkoxides. 

The addition of an acid to the wash solution will prevent the hydrolysis of iron(III) or similar salts thus dilute hydrochloric acid will serve to remove iron(III) and aluminium salts from precipitates that are insoluble in this acid. 

Hydrolysis of iron(III) — chaotic olation versus nucleation. W. Schneider, Comments Inorg. Chem., 1984,3,205-223 (38). 

Hydrolysis of Iron(lll) in Acid Media - Formation of Polynuclear Species... 

Schneider, W., and B. Schwyn (1987), "The Hydrolysis of Iron in Synthetic, Biological and Aquatic Media", in W. Stumm, Ed., Aquatic Surface Chemistry, John Wiley and Sons, New York, 167-196. 

Reaction kinetics and mechanisms for oxidation of [Fe(diimine)2(CN)2], [Fe(diimine)(CN)4] (diimine = bipy or phen) (and indeed [Fe(CN)6] ) by peroxoanions such as (S20g, HSOs", P20g ) have been reviewed. Reactivity trends have been established, and initial state— transition state analyses carried out, for peroxodisulfate oxidation of [Fe(bipy)2(CN)2], [Fe(bipy)(CN)4] , and [Fe(Me2bsb)(CN)4] in DMSO—water mixtures. Whereas in base hydrolysis of iron(II)-diimine complexes reactivity trends in binary aqueous solvent mixtures are generally determined by hydroxide solvation, in these peroxodisulfate oxidations solvation changes for both partners affect the observed pattern. ... 

Dang, M.-Z. Rancourt, D.G. Dutrizac J.E. La-marche, G. Provencher, R. (1998) Interplay of surface conditions, particle size, stoichiometry, cell parameters, and magnetism in synthetic hematite-like materials. Hyperfme Interactions 117 271-319 Daniele, P.G. Rigano, C. Sammartano, S. Zeland,V. (1994) Ionic strength dependence of formation constants - XVIII. The hydrolysis of iron(III) in aqueous KNOj solutions.Ta-lanta41 1577-1582... 

Haigh, C.J. (1967) The hydrolysis of iron in acid solution. Proc. Aust. Inst. Mining Metal 223 49-56... 

Ozeki, S. Uehiyama, H. Katada, K. (1994) Hydrolysis of iron ions in chrysotile nanotubes a template effect on crystal growth. Langmuir 10 923-928... 

Schneider, W. Schwyn, B. (1987) The hydrolysis of iron in synthetic, biological, and aquatic media. In Stumm,W. (ed.) Aquatic surface chemistry. Wiley Interscience, New York, 167-194... 

In the first study of hydrolysis of Fe(OEt)3 carried out by Thiessen et al. [1577], the precipitate of cubic crystals Fe203 4H20 was obtained after refluxing of diluted alcoholic solution of iron ethoxide for a few hours. Hydrolysis of iron ethoxide by excess of water results in amorphous precipitate, which on thermal treatment at first gives y-Fe203 and then a-Fe203 (in contrast to the precipitates of (X-FeOOH, which precipitate from aqueous solutions) [1776]. 

See, for example, J. Steinhardt and J. A. Reynolds, Multiple Equilibria in Proteins, Academic Press, 1969 K. S. Murray, Binuclear oxo-bridged iron(III) complexes, Coord. Chem. Rev. 12 1 (1974) W. Schneider and B. Schwyn, The hydrolysis of iron in synthetic, biological, and aquatic media, pp. 167-196, in Aquatic Surface Chemistry, ed. by W. Stumm, Wiley, New York, 1987 and P. M. Bertsch, Aqueous polynuclear aluminum species, pp. 87 115 in The Environmental Chemistry of Aluminum, ed. by G. Spnsitn, CRC Press, Boca Raton, FL, 1989. 

Iron is deposited from volcanogenic hydrothermal waters either on their way to the sea basin or when they mix with sea waters upon entering the basin. The main cause of precipitation of iron as sediment is a decrease in acidity of the water, due to dilution with atmospheric or sea water or due to reaction with the wall rocks, to pH values exceeding those of the beginning of hydrolysis of iron. 

Hydrolysis reactions of many cations are more complicated than (7-16) implies. Metal ions usually cannot be treated as simple polybasic acids. In particular, metal ions of charge 2 or greater may have a pronounced tendency to form ionic species containing more than one metal atom. Thus Hedstrdm deduced that the hydrolysis of iron(II) could be represented by the single reaction... 

Citric acid dissociation and the hydrolysis of iron(ni) and aluminum 375... 

CITRIC ACID DISSOCIATION AND THE HYDROLYSIS OF IRON(III) AND ALUMINUM... 

Daniele, P. G., Rigano, C., Sammartano, S., and Zelano, V. (1994). Ionic strength dependence of formation constants, XVIH The hydrolysis of iron(III) in aqueous KNO3 solution. Talanta 41, 1577-1582. 

Mineral, middle part Mineral, lower part Cl Plagioclase Carbonic acid low CO2 partial pressure Oxidation and hydrolysis of iron Fe(II-III) + H2O -H 02->Fe00H-HH+ (Primary/secondary Al-silicate) + H2CO3 -t-H20 (secondary Al-silicate/hydroxide) -H (Mg, Ca, Na, K)+ + HCO + H4Si04 (Primary Fe-Al-silicate) + + H20- (secondary Al-silicate) -I- (Fe-oxide/ hydroxide) -1- H H- H4Si04 Slow incongruent dissolution Very slow incongruent dissolution... 

C3 Amphibole Oxidation and hydrolysis of iron Fe(II-III) + H2O + Oj FeOOH + H (Primary Fe-silicate) 4- H 4- H2O—> (Fe-oxide/hydroxide) 4- H" 4- H4Si04 Extremely slow incongruent dissolution... 

Peroxo-diiron(III) complexes can undergo not only redox but also ligand substitution reactions. Liberation of H202 was observed in the reactions with phenols and carboxylic acids leading also to the respective phenolate or carboxylate iron(III) complexes.86 Hydrolysis of a peroxo-diiron(III) complex results in an oxo-diiron(III) species and hydrogen peroxide. Such reaction is responsible for the autoxidation of hemerythrin, but is very slow for the native protein due to hydrophobic shielding of the active site (Section 4.2.3).20 The hydrolysis of iron(III) peroxides is reversible, and the reverse reaction, the formation of peroxo intermediates from H202 and the (di)iron(III), is often referred to as peroxide shunt and is much better studied for model complexes. 

The hydrolysis of iron(III) continues progressively at still higher pH, giving... 

Doelsch E, Rose J, Masion A, Bottero JY, Nahon D, Bertsch PM (2002) Hydrolysis of iron(TI) chloride under anoxic conditions and influence of Si04 ligands. Langmuir 18 4292-4299 Doyle CS, Carrier X, Kendelewicz T, Brown GE Jr (1999b) Reaction of C02 with CaO(lOO) surfaces. Surf Rev Lett 6 1247-1254... 

Using a similar procedure, smaller magnetic particles (400-700 nm in diameter) were produced by Lindlar et al. [175], Polymer particles of poly(MMA-co-GMA) were first synthesized by surfactant-free emulsion polymerization. Ethylene diamine, was then the added to obtain internal anchor groups able to favor the subsequent impregnation and hydrolysis of iron salts inside the particles. The final composite particles were monodisperse in size and the magnetic loading was close to 25 wt%. 

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