Editing Iron(III) oxide (section)

==Uses==

===Iron industry===
The overwhelming application of iron(III) oxide is as the feedstock of the steel and iron industries, e.g., the [[smelting|production of iron]], steel, and many alloys.<ref name=Ullmann>{{cite book |last1=Greenwood |first1=N. N. |last2=Earnshaw |first2=A. |year=1997 |title=Chemistry of the Element |edition=2nd |location=Oxford |publisher=Butterworth-Heinemann |isbn=978-0-7506-3365-9 }}</ref> Iron oxide (Fe2O3) has been used in stained glass since the medieval period, with evidence suggesting its use in stained glass production dating back to the early Middle Ages, where it was primarily used to create yellow, orange, and red colors in the glass, still being used for industrial purposes today.<ref>{{Cite web |last=Golchha |first=Vipul |title=About Iron Oxide Pigments |url=https://www.golchhaoxides.com/iron-oxide-pigments.php#:~:text=Iron%20Oxides%20have%20been%20used,drawings%20to%20ensure%20bountiful%20hunting. |access-date=2024-10-29 |website=Golchha Oxides Pvt Ltd |language=en}}</ref><ref>{{Cite web |title=Iron(III) Oxide - Structure, Properties, Uses of Fe2O3 |url=https://byjus.com/chemistry/fe2o3/#:~:text=Ferric%20oxide%20(Fe2O,glass,%20diamonds%20and%20precious%20metals. |access-date=2024-10-29 |website=BYJUS |language=en}}</ref>

===Polishing===
A very fine powder of ferric oxide is known as "jeweler's rouge", "red rouge", or simply rouge. It is used to put the final polish on metallic [[jewellery|jewelry]] and [[lens (optics)|lenses]], and historically as a [[rouge (cosmetics)|cosmetic]]. Rouge cuts more slowly than some modern polishes, such as [[cerium(IV) oxide]], but is still used in optics fabrication and by jewelers for the superior finish it can produce. When polishing gold, the rouge slightly stains the gold, which contributes to the appearance of the finished piece. Rouge is sold as a powder, paste, laced on polishing cloths, or solid bar (with a [[wax]] or [[petroleum|grease]] binder). Other polishing compounds are also often called "rouge", even when they do not contain iron oxide. Jewelers remove the residual rouge on jewelry by use of [[ultrasonic cleaning]]. Products sold as "[[stropping (blade)|stropping]] compound" are often applied to a [[razor strop|leather strop]] to assist in getting a razor edge on knives, straight razors, or any other edged tool.

===Pigment===
{{multiple image|align = left
| footer = Sample of the red α- and yellow β-phases of hydrated of iron(III) oxide;<ref name=doc00 /> both are useful as pigments.
| width1 = 220|image1 = Iron oxide red y.jpg
| width2 = 178|image2 = Iron oxide yellow.jpg
}}
Iron(III) oxide is also used as a [[pigment]], under names "Pigment Brown 6", "Pigment Brown 7", and "Pigment Red 101".<ref>{{cite book |title=Paint and Surface Coatings: Theory and Practice |publisher=William Andrew Inc. |isbn=978-1-884207-73-0 |year= 1999}}</ref> Some of them, e.g., Pigment Red 101 and Pigment Brown 6, are approved by the US [[Food and Drug Administration]] (FDA) for use in cosmetics. [[Iron oxides]] are used as pigments in dental composites alongside titanium oxides.<ref>{{cite book|last=Banerjee|first=Avijit|title=Pickard's Manual of Operative Dentistry|year=2011|publisher=Oxford University Press Inc., New York|location=United States|isbn=978-0-19-957915-0|pages=89}}</ref>

Hematite is the characteristic component of the Swedish paint color [[Falu red]].

===Magnetic recording===
Iron(III) oxide was the most common [[magnet]]ic particle used in all types of [[magnetic storage|magnetic storage and recording]] media, including magnetic disks (for data storage) and [[magnetic tape]] (used in audio and video recording as well as data storage). Its use in computer disks was superseded by cobalt alloy, enabling thinner magnetic films with higher storage density.<ref>{{cite journal|doi=10.1063/1.2750414|title=Perpendicular recording media for hard disk drives|journal=Journal of Applied Physics|volume=102|issue=1|pages=011301–011301–22|year=2007|last1=Piramanayagam|first1=S. N.|bibcode=2007JAP...102a1301P}}</ref>

===Photocatalysis===
α-{{chem2|Fe2O3}} has been studied as a [[photoanode]] for solar water oxidation.<ref name=Kay2006>{{cite journal|author=Kay, A. |author2=Cesar, I. |author3=Grätzel, M.|title=New Benchmark for Water Photooxidation by Nanostructured α-Fe<sub>2</sub>O<sub>3</sub> Films |journal=Journal of the American Chemical Society |volume=128 |issue=49 |pages=15714–15721 |doi=10.1021/ja064380l |pmid=17147381 |year=2006 }}</ref> However, its efficacy is limited by a short diffusion length (2–4&nbsp;nm) of photo-excited charge carriers<ref>{{cite journal|author=Kennedy, J.H.|author2=Frese, K.W.|title=Photooxidation of Water at α-Fe<sub>2</sub>O<sub>3</sub> Electrodes|journal=Journal of the Electrochemical Society|volume=125|issue=5|pages=709|doi=10.1149/1.2131532|year=1978|bibcode=1978JElS..125..709K }}</ref> and subsequent fast [[Electron-hole recombination|recombination]], requiring a large [[overpotential]] to drive the reaction.<ref>{{cite journal|author=Le Formal, F. |title=Back Electron–Hole Recombination in Hematite Photoanodes for Water Splitting |journal=Journal of the American Chemical Society |volume=136 |issue=6 |pages=2564–2574 |doi=10.1021/ja412058x |pmid=24437340 |year=2014 |doi-access=free }}</ref> Research has been focused on improving the water oxidation performance of {{chem2|Fe2O3}} using nanostructuring,<ref name=Kay2006 /> surface functionalization,<ref>{{cite journal|author=Zhong, D.K. |author2=Gamelin, D.R.|title=Photoelectrochemical Water Oxidation by Cobalt Catalyst ("Co−Pi")/α-Fe<sub>2</sub>O<sub>3</sub> Composite Photoanodes: Oxygen Evolution and Resolution of a Kinetic Bottleneck |journal=Journal of the American Chemical Society |volume=132 |issue=12 |pages=4202–4207 |doi=10.1021/ja908730h |pmid=20201513 |year=2010 }}</ref> or by employing alternate crystal phases such as β-{{chem2|Fe2O3}}.<ref>{{cite journal|author=Emery, J.D. |title=Atomic Layer Deposition of Metastable β-Fe<sub>2</sub>O<sub>3</sub> via Isomorphic Epitaxy for Photoassisted Water Oxidation|journal=ACS Applied Materials & Interfaces|volume=6|issue=24|pages=21894–21900|doi=10.1021/am507065y|pmid=25490778|year=2014|osti=1355777}}</ref>

===Medicine===
[[Calamine]] lotion, used to treat mild [[itch]]iness, is chiefly composed of a combination of [[zinc oxide]], acting as [[astringent]], and about 0.5% iron(III) oxide, the product's active ingredient, acting as [[antipruritic]]. The red color of iron(III) oxide is also mainly responsible for the lotion's pink color.