Iron oxide 277266 224632717 2008-07-09T19:11:05Z 89.238.26.220 :''[[Ferruginous]] redirects here. For the bird, see [[Ferruginous Hawk]]'' [[Image:IronOxidePigmentUSGOV.jpg|thumb|Iron oxide pigment]] Altogether there are sixteen known [[iron]] [[oxide]]s and oxyhydroxides.<ref>{{cite book | last = Cornell | first = RM | coauthors = Schwertmann, U | title = The iron oxides: structure, properties, reactions, occurrences and uses | year = 2003 | publisher = Wiley VCH | id = ISBN 3-527-30274-3 }}</ref> ==Oxides== * FeO, [[iron(II) oxide]], ([[wüstite]]) * Fe<sub>3</sub>O<sub>4</sub>, [[iron(II,III) oxide]], ([[magnetite]]) * Fe<sub>2</sub>O<sub>3</sub>, [[iron(III) oxide]] ** α-Fe<sub>2</sub>O<sub>3</sub>, [[hematite]] ** β-Fe<sub>2</sub>O<sub>3</sub> ** γ-Fe<sub>2</sub>O<sub>3</sub>, [[maghemite]] ** ε-Fe<sub>2</sub>O<sub>3</sub> ==Hydroxides== * [[iron(II) hydroxide]] (Fe(OH)<sub>2</sub>) * [[iron(III) hydroxide]] (Fe(OH)<sub>3</sub>), ([[bernalite]]) ==Oxide-hydroxides== * [[goethite]] (α-FeOOH), * [[akaganéite]] (β-FeOOH), * [[lepidocrocite]] (γ-FeOOH), * [[feroxyhyte]] (δ-FeOOH), * [[ferrihydrite]] (Fe<sub>5</sub>HO<sub>8</sub>·4H<sub>2</sub>O approx.) * high-pressure FeOOH * [[schwertmannite]] * [[green rusts]] Fe<sup>III</sup><sub>x</sub>Fe<sup>II</sup><sub>y</sub>(OH)<sub>3x+2y-z</sub>(A<sup>-</sup>)<sub>z</sub>; where A<sup>-</sup> is Cl<sup>-</sup> or 0.5SO<sub>4</sub><sup>2-</sup> ==Uses== Some iron oxides are widely used in [[ceramic]] applications, particularly in [[ceramic glaze|glazing]]. Many metal oxides provide the colors in glazes after being fired at high temperatures. Iron oxides yield [[pigment]]s (see [[:Category:Iron oxide pigments|Iron oxide pigments]]). Natural iron oxides pigments are called [[ocher]]s. Many classic paint colors, such as raw and burnt [[sienna]]s and [[umber]]s, are iron-oxide pigments. These pigments have been used in art since the earliest prehistoric art known, the [[cave painting]]s at [[Lascaux]] and nearby sites. Iron (III) oxide is typically used. Iron pigments are also widely used in the cosmetic field. They are considered to be nontoxic, moisture resistant, and nonbleeding. Iron oxides graded safe for cosmetic use are produced synthetically in order to avoid the inclusion of ferrous or ferric oxides, and impurities normally found in naturally occurring iron oxides. Typically, the Iron(II) oxide pigment is black, while the Iron(III) oxide is red or rust-colored. (Iron compounds other than oxides can be other colors.) Magnetite (under the name Black Oxide) is used for coating steel tools <ref>[http://www.epi.com/black-oxide/blackoxide-faq.htm Black Oxide FAQ - EPI - Electrochemical Products, Inc<!-- Bot generated title -->]</ref>. This protects them from corrosion and gives a pleasing appearance. A grade of hematite called [[MIO]] (micaceous iron oxide) is used as anti-corrosion paint (many bridges, Eiffel tower). Iron oxides are used as contrast agent in [[Magnetic Resonance Imaging]], to shorten proton [[Relaxation (NMR)|relaxation times]], (T1, T2 and T2*). The superparamagnetic contrast agents are composed of a water insoluble crystalline magnetic core, usually magnetite (Fe3O4) or maghemite (γ-Fe2O3). The mean core diameter ranges from 4 to 10 nm. This crystalline core is often surrounded by a layer of dextran or starch derivatives. The total size of the particle is expressed as the mean hydrated particle diameter. USPIO, Ultrasmall Superparamagnetic Iron Oxide nanoparticles, which usually have single crystal cores, have a mean hydrated particle diameter less than 50 nm. ==Properties== *[[Iron(II) oxide]] (FeO) or ferrous oxide is also known as [[wüstite]] in its mineral form. As a [[Powder (substance)|powder]] this black oxide can cause [[explosion]]s as it readily [[Combustion|ignites]]. *[[Iron(III) oxide]] (Fe<sub>2</sub>O<sub>3</sub>) or ferric oxide is also known as [[hematite]] (alpha form) or [[maghemite]] (gamma form) in its mineral form. As an industrial chemical it is commonly called [[Jeweller's rouge|rouge]]. Purified, it is used as a [[coating]] in [[magnetic storage|magnetic]] audio and computer media. In a dry or alkaline environment it can cause [[passivation]] and inhibits [[rust]], yet it is also a major component of rust. *[[Iron(II,III) oxide]] (Fe<sub>3</sub>O<sub>4</sub>) or ferrous ferric oxide is also known as magnetite or [[lodestone]] in its mineral form, a major iron ore. Magnetite forms readily when iron [[oxidize]]s underwater, and so is often found inside tanks or below the waterline of ships. It is not difficult to extract iron from ore as compared with the similarly abundant <!-- in the crust --> elements [[aluminium]] and [[titanium]]. ==References== <references /> ==External links== * [http://www.nano-oxides.com/pdf/Fe2O3_Brochure.pdf Information from Nano-Oxides, Inc. on Fe<sub>2</sub>O<sub>3</sub>.] * http://chemed.chem.purdue.edu/demos/demosheets/12.3.html * http://minerals.usgs.gov/minerals/pubs/commodity/iron_oxide/ [[Category:Iron compounds]] [[Category:Oxides]] [[Category:Iron oxide pigments]] [[de:Eisen#Oxide]] [[eo:Fera oksido]] [[es:Óxidos de hierro]] [[fi:Rautaoksidi]] [[fr:Oxyde de fer]] [[ko:산화 철]] [[hr:Željezovi oksidi]] [[la:Ferri Oxida]] [[hu:Vas-oxid]] [[ja:酸化鉄]] [[nl:IJzeroxide]] [[no:Jernoksider]] [[pl:Tlenek żelaza]] [[pt:Óxido de ferro]] [[ru:Оксиды железа]] [[simple:Iron oxide]] [[sv:Järnoxid]] [[vi:Ôxít sắt]]