Iron(III) oxide-hydroxide

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Iron(III) oxide-hydroxide
Hydroxid zelezity.PNG
Names
IUPAC name
Iron(III) oxide-hydroxide
Other names
Metaferric acid
Ferric oxyhydroxide
Goethite
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.039.754 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 215-176-6
MeSH Goethite
PubChem CID
UNII
  • InChI=1S/Fe.H2O.O/h;1H2;/q+1;;/p-1 Yes check.svgY
    Key: AEIXRCIKZIZYPM-UHFFFAOYSA-M Yes check.svgY
  • O=[Fe]O
Properties
FeO(OH)
AppearanceVivid, dark orange, opaque crystals
Odor odorless
Density 4.25 g/cm3
insoluble at pH 7
2.79×10−39 for Fe(OH)3 [1]
Hazards
NFPA 704 (fire diamond)
NFPA 704.svgHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
1
0
0
Pharmacology
B03AB04 ( WHO )
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Yes check.svgY  verify  (what is  Yes check.svgYX mark.svgN ?)

Iron(III) oxide-hydroxide or ferric oxyhydroxide [2] is the chemical compound of iron, oxygen, and hydrogen with formula FeO(OH).

Contents

The compound is often encountered as one of its hydrates, FeO(OH)·n H
2O [rust]. The monohydrate FeO(OH)·H
2O is often referred to as iron(III) hydroxideFe(OH)
3, [3] hydrated iron oxide, yellow iron oxide, or Pigment Yellow 42. [3]

Natural occurrences

Minerals

Anhydrous ferric hydroxide occurs in the nature as the exceedingly rare mineral bernalite, Fe(OH)3·nH2O (n = 0.0–0.25). [4] [5] Iron oxyhydroxides, FeOOH, are much more common and occur naturally as structurally different minerals (polymorphs) denoted by the Greek letters α, β, γ and δ.

Non-mineral

Goethite and lepidocrocite, both crystallizing in orthorhombic system, are the most common forms of iron(III) oxyhydroxide and the most important mineral carriers of iron in soils.

Mineraloids

Iron(III) oxyhydroxide is the main component of other minerals and mineraloids:

Properties

The color of iron(III) oxyhydroxide ranges from yellow through dark-brown to black, depending on the degree of hydration, particle size and shape, and crystal structure.

Structure

The crystal structure of β-FeOOH (akaganeite) is that of hollandite or BaMn
8O
16. The unit cell is tetragonal with a = 1.048 and c = 0.3023 nm, and contains eight formula units of FeOOH. Its dimensions are about 500 × 50 × 50 nm. Twinning often produces particles with the shape of hexagonal stars. [2]

Chemistry

On heating, β-FeOOH decomposes and recrystallizes as α-Fe
2O
3 (hematite). [2]

Uses

Limonite, a mixture of various hydrates and polymorphs of ferric oxyhydroxide, is one of the three major iron ores, having been used since at least 2500 BC. [8] [9]

Yellow iron oxide, or Pigment Yellow 42, is Food and Drug Administration (FDA) approved for use in cosmetics and is used in some tattoo inks.

Iron oxide-hydroxide is also used in aquarium water treatment as a phosphate binder. [10]

Iron oxide-hydroxide nanoparticles have been studied as possible adsorbents for lead removal from aquatic media. [11]

Medication

Iron polymaltose is used in treatment of iron-deficiency anemia.

Production

Iron(III) oxyhydroxide precipitates from solutions of iron(III) salts at pH between 6.5 and 8. [12] Thus the oxyhydroxide can be obtained in the lab by reacting an iron(III) salt, such as ferric chloride or ferric nitrate, with sodium hydroxide: [13]

FeCl
3 + 3 NaOH → Fe(OH)
3 + 3 NaCl
Fe(NO
3)
3 + 3 NaOH → Fe(OH)
3 + 3 NaNO
3

In fact, when dissolved in water, pure FeCl
3 will hydrolyze to some extent, yielding the oxyhydroxide and making the solution acidic: [12]

FeCl
3 + 2 H
2O ↔ FeOOH + 3 HCl

Therefore, the compound can also be obtained by the decomposition of acidic solutions of iron(III) chloride held near the boiling point for days or weeks: [14]

FeCl
3 + 2 H
2O → FeOOH(s) + 3 HCl(g)

(The same process applied to iron(III) nitrate Fe(NO
3)
3 or perchlorate Fe(ClO
4)
3 solutions yields instead particles of α-Fe
2O
3. [14] )

Another similar route is the decomposition of iron(III) nitrate dissolved in stearic acid at about 120 °C. [15]

The oxyhydroxide prepared from ferric chloride is usually the β polymorph (akaganeite), often in the form of thin needles. [14] [16]

The oxyhydroxide can also be produced by a solid-state transformation from iron(II) chloride tetrahydrate FeCl
2·4H
2O. [6]

The compound also readily forms when iron(II) hydroxide is exposed to air:

4Fe(OH)
2 + O
2 → 4 FeOOH + 2 H
2O

The iron(II) hydroxide can also be oxidized by hydrogen peroxide in the presence of an acid:

2Fe(OH)
2 + H
2O
2 → 2 Fe(OH)
3

See also

Related Research Articles

<span class="mw-page-title-main">Limonite</span> Hydrated iron oxide mineral

Limonite is an iron ore consisting of a mixture of hydrated iron(III) oxide-hydroxides in varying composition. The generic formula is frequently written as FeO(OH)·nH2O, although this is not entirely accurate as the ratio of oxide to hydroxide can vary quite widely. Limonite is one of the three principal iron ores, the others being hematite and magnetite, and has been mined for the production of iron since at least 400 BC.

<span class="mw-page-title-main">Goethite</span> Iron(III) oxide-hydroxide named in honor to the poet Goethe

Goethite is a mineral of the diaspore group, consisting of iron(III) oxide-hydroxide, specifically the α-polymorph. It is found in soil and other low-temperature environments such as sediment. Goethite has been well known since ancient times for its use as a pigment. Evidence has been found of its use in paint pigment samples taken from the caves of Lascaux in France. It was first described in 1806 based on samples found in the Hollertszug Mine in Herdorf, Germany. The mineral was named after the German polymath and poet Johann Wolfgang von Goethe (1749–1832).

<span class="mw-page-title-main">Ferric</span> The element iron in its +3 oxidation state

In chemistry, Ferric refers to the element iron in its +3 oxidation state. Ferric chloride is an alternative name for iron(III) chloride (FeCl3). The adjective ferrous is used instead for iron(II) salts, containing the cation Fe2+. The word ferric is derived from the Latin word ferrum, meaning "iron".

<span class="mw-page-title-main">Iron(III) oxide</span> Chemical compound

Iron(III) oxide or ferric oxide is the inorganic compound with the formula Fe2O3. It is one of the three main oxides of iron, the other two being iron(II) oxide (FeO), which is rare; and iron(II,III) oxide (Fe3O4), which also occurs naturally as the mineral magnetite. As the mineral known as hematite, Fe2O3 is the main source of iron for the steel industry. Fe2O3 is readily attacked by acids. Iron(III) oxide is often called rust, since rust shares several properties and has a similar composition; however, in chemistry, rust is considered an ill-defined material, described as hydrous ferric oxide.

<span class="mw-page-title-main">Iron oxide</span> Class of chemical compounds composed of iron and oxygen

Iron oxides are chemical compounds composed of iron and oxygen. Several iron oxides are recognized. Often they are non-stoichiometric. Oxyhydroxides are a related class of compounds, perhaps the best known of which is rust.

<span class="mw-page-title-main">Manganese dioxide</span> Chemical compound

Manganese dioxide is the inorganic compound with the formula MnO
2. This blackish or brown solid occurs naturally as the mineral pyrolusite, which is the main ore of manganese and a component of manganese nodules. The principal use for MnO
2 is for dry-cell batteries, such as the alkaline battery and the zinc–carbon battery. MnO
2 is also used as a pigment and as a precursor to other manganese compounds, such as KMnO
4. It is used as a reagent in organic synthesis, for example, for the oxidation of allylic alcohols. MnO
2 has an α-polymorph that can incorporate a variety of atoms in the "tunnels" or "channels" between the manganese oxide octahedra. There is considerable interest in α-MnO
2 as a possible cathode for lithium-ion batteries.

Iron(III) chloride describes the inorganic compounds with the formula FeCl3(H2O)x. Also called ferric chloride, these compounds are some of the most important and commonplace compounds of iron. They are available both in anhydrous and in hydrated forms which are both hygroscopic. They feature iron in its +3 oxidation state. The anhydrous derivative is a Lewis acid, while all forms are mild oxidizing agents. It is used as a water cleaner and as an etchant for metals.

<span class="mw-page-title-main">Iridium(III) chloride</span> Chemical compound

Iridium(III) chloride is the inorganic compound with the formula IrCl3. The anhydrous compound is relatively rare, but the related hydrate is much more commonly encountered. The anhydrous salt has two polymorphs, α and β, which are brown and red colored respectively. More commonly encountered is the hygroscopic dark green trihydrate IrCl3(H2O)3 which is a common starting point for iridium chemistry.

<span class="mw-page-title-main">Akaganeite</span> Iron(III) oxide-hydroxide mineral

Akaganeite, also written as the deprecated Akaganéite, is a chloride-containing iron(III) oxide-hydroxide mineral, formed by the weathering of pyrrhotite (Fe1−xS).

<span class="mw-page-title-main">Nickel(II) hydroxide</span> Chemical compound

Nickel(II) hydroxide is the inorganic compound with the formula Ni(OH)2. It is a lime-green solid that dissolves with decomposition in ammonia and amines and is attacked by acids. It is electroactive, being converted to the Ni(III) oxy-hydroxide, leading to widespread applications in rechargeable batteries.

<span class="mw-page-title-main">Iron(III) nitrate</span> Chemical compound

Iron(III) nitrate, or ferric nitrate, is the name used for a series of inorganic compounds with the formula Fe(NO3)3.(H2O)n. Most common is the nonahydrate Fe(NO3)3.(H2O)9. The hydrates are all pale colored, water-soluble paramagnetic salts.

In inorganic chemistry, mineral hydration is a reaction which adds water to the crystal structure of a mineral, usually creating a new mineral, commonly called a hydrate.

<span class="mw-page-title-main">Ferrihydrite</span> Iron oxyhydroxide mineral

Ferrihydrite (Fh) is a widespread hydrous ferric oxyhydroxide mineral at the Earth's surface, and a likely constituent in extraterrestrial materials. It forms in several types of environments, from freshwater to marine systems, aquifers to hydrothermal hot springs and scales, soils, and areas affected by mining. It can be precipitated directly from oxygenated iron-rich aqueous solutions, or by bacteria either as a result of a metabolic activity or passive sorption of dissolved iron followed by nucleation reactions. Ferrihydrite also occurs in the core of the ferritin protein from many living organisms, for the purpose of intra-cellular iron storage.

<span class="mw-page-title-main">Barium ferrate</span> Chemical compound

Barium ferrate is the chemical compound of formula BaFeO4. This is a rare compound containing iron in the +6 oxidation state. The ferrate(VI) ion has two unpaired electrons, making it paramagnetic. It is isostructural with BaSO4, and contains the tetrahedral [FeO4]2− anion.

<span class="mw-page-title-main">Green rust</span> Generic name for various green-colored iron compounds

Green rust is a generic name for various green crystalline chemical compounds containing iron(II) and iron(III) cations, the hydroxide (HO−
) anion, and another anion such as carbonate (CO2−
3), chloride (Cl−
), or sulfate (SO2−
4), in a layered double hydroxide structure. The most studied varieties are

Siderogel is an amorphous mineral consisting of iron(III) oxide-hydroxide FeO(OH), the same chemical compound as limonite and goethite; or possibly an hydrate of the same FeO(OH)•nH
2O.

Cobalt compounds are chemical compounds formed by cobalt with other elements.

Iron ochre or iron ocher (Ancient Greek: ὠχρός, pale yellow, orange) — at least three iron ore minerals, common abrasives and pigments with a red-brown or brown-orange hue and the powdery consistency of ocher, were known under such a trivial name. The term “iron ocher” was primarily used among mineral collectors, geologists, miners and representatives of related craft professions. It may refer to:

References

  1. ↑ "Solubility product constants at 25 oC". Archived from the original on 2015-02-26. Retrieved 2015-02-23.
  2. 1 2 3 A. L. Mackay (1960): "β-Ferric Oxyhydroxide". Mineralogical Magazine (Journal of the Mineralogical Society), volume 32, issue 250, pages 545-557. doi : 10.1180/minmag.1960.032.250.04
  3. 1 2 CAS 51274-00-1 , C.I. 77492
  4. ↑ "Bernalite".
  5. ↑ "List of Minerals". 21 March 2011.
  6. 1 2 A. L. Mackay (1962): "β-Ferric oxyhydroxide—akaganéite", Mineralogical Magazine (Journal of the Mineralogical Society), volume 33, issue 259, pages 270-280 doi : 10.1180/minmag.1962.033.259.02
  7. ↑ C. Rémazeilles and Ph. Refait (2007): "On the formation of β-FeOOH (akaganéite) in chloride-containing environments". Corrosion Science, volume 49, issue 2, pages 844-857. doi : 10.1016/j.corsci.2006.06.003
  8. ↑ MacEachern, Scott (1996): "Iron Age beginnings north of the Mandara Mountains, Cameroon and Nigeria". InIn Pwiti, Gilbert and Soper, Robert (editors) (1996) Aspects of African Archaeology: Proceedings of the Tenth Pan-African Congress University of Zimbabwe Press, Harare, Zimbabwe, ISBN   978-0-908307-55-5, pages 489-496. Archived here on 2012-03-11.
  9. ↑ Diop-Maes, Louise Marie (1996): "La question de l'Âge du fer en Afrique" ("The question of the Iron Age in Africa"). Ankh, volume4/5, pages 278-303. Archived on 2008-01-25.
  10. ↑ Iron Oxide Hydroxide (GFO) Phosphate Binders
  11. ↑ Safoora Rahimi, Rozita M. Moattari, Laleh Rajabi, Ali Ashraf Derakhshan, and Mohammad Keyhani (2015): "Iron oxide/hydroxide (α,γ-FeOOH) nanoparticles as high potential adsorbents for lead removal from polluted aquatic media". Journal of Industrial and Engineering Chemistry, volume 23, pages 33-43. doi : 10.1016/j.jiec.2014.07.039
  12. 1 2 Tim Grundl and Jim Delwiche (1993): "Kinetics of ferric oxyhydroxide precipitation". Journal of Contaminant Hydrology, volume 14, issue 1, pages 71-87. doi : 10.1016/0169-7722(93)90042-Q
  13. ↑ K. H. Gayer and Leo Woontner (1956): "The Solubility of Ferrous Hydroxide and Ferric Hydroxide in Acidic and Basic Media at 25°". Journal of Physical Chemistry, volume 60, issue 11, pages 1569–1571. doi : 10.1021/j150545a021
  14. 1 2 3 Egon Matijević and Paul Scheiner (1978): "Ferric hydrous oxide sols: III. Preparation of uniform particles by hydrolysis of Fe(III)-chloride, -nitrate, and -perchlorate solutions". Journal of Colloid and Interface Science, volume 63, issue 3, pages 509-524. doi : 10.1016/S0021-9797(78)80011-3
  15. ↑ Dan Li, Xiaohui Wang, Gang Xiong, Lude Lu, Xujie Yang and Xin Wang (1997): "A novel technique to prepare ultrafine Fe
    2    O
    3     via hydrated iron(III) nitrate". Journal of Materials Science Letters volume 16, pages 493–495 doi : 10.1023/A:1018528713566
  16. ↑ Donald O. Whittemore and Donald Langmuir (1974): "Ferric Oxyhydroxide Microparticles in Water". Environmental Health Perspective, volume 9, pages 173-176. doi : 10.1289/ehp.749173
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