'''Ferrate''' loosely refers to a material that can be viewed as containing anionic iron complexes. The term ferrate derives {{etymology|la|ferrum|iron}}.
Examples include tetrachloroferrate ([FeCl<sub>4</sub>]<sup>2−</sup>), oxyanions (e.g. {{chem|FeO|4|2-}}), and the organoferrates, including highly reduced tetracarbonylferrate ([Fe(CO)<sub>4</sub>]<sup>2−</sup>) salts.<ref name="Greenwood&Earnshaw2nd">{{Greenwood&Earnshaw2nd}}</ref>{{Page needed|date=March 2020}} Although rarely studied, ferrate(V) [FeO<sub>4</sub>]<sup>3−</sup> and ferrate(IV) [FeO<sub>4</sub>]<sup>4−</sup> oxyanions of iron also exist. These too are called ferrates.<ref name="hill">{{cite book | title = Chemistry in context | author1 = Graham Hill | author2 = John Holman | edition = 5th | publisher = Nelson Thornes | year = 2000 | isbn = 0-17-448276-0 | page = 202 }}</ref> <gallery class="center" caption="Ferrates" widths="180px" heights="120px" > File:Disodium tetracarbonylferrate.png|Disodium salt of tetracarbonylferrate File:Ferrate ion.svg|Structure of ferrate(VI), [FeO<sub>4</sub>]<sup>2−</sup> File:1-Butyl-3-methylimidazolium tetrachloroferrate.svg|1-Butyl-3-methylimidazolium salt of [FeCl<sub>4</sub>]<sup>−</sup> File:Potassium-trioxalatoferrate(III)-2D.png|Potassium tris(oxalato)ferrate </gallery>
Ferrate(VI) is a strong oxidizer,<ref>{{Cite journal |last=Sharma |first=Virender K. |date=2002-03-01 |title=Potassium ferrate(VI): an environmentally friendly oxidant |url=https://www.sciencedirect.com/science/article/pii/S1093019101001198 |journal=Advances in Environmental Research |volume=6 |issue=2 |pages=143–156 |doi=10.1016/S1093-0191(01)00119-8 |bibcode=2002AdvER...6..143S |issn=1093-0191|url-access=subscription }}</ref> used in water purification<ref>{{Cite journal |last1=Licht |first1=Stuart |last2=Yu |first2=Xingwen |date=2005-10-01 |title=Electrochemical Alkaline Fe(VI) Water Purification and Remediation |url=https://pubs.acs.org/doi/10.1021/es051084k |journal=Environmental Science & Technology |language=en |volume=39 |issue=20 |pages=8071–8076 |doi=10.1021/es051084k |pmid=16295877 |bibcode=2005EnST...39.8071L |issn=0013-936X|url-access=subscription }}</ref> and battery technology.<ref>{{Cite journal |last1=Licht |first1=Stuart |last2=Wang |first2=Baohui |last3=Ghosh |first3=Susanta |date=1999-08-13 |title=Energetic Iron(VI) Chemistry: The Super-Iron Battery |url=https://www.science.org/doi/10.1126/science.285.5430.1039 |journal=Science |language=en |volume=285 |issue=5430 |pages=1039–1042 |doi=10.1126/science.285.5430.1039 |pmid=10446044 |issn=0036-8075|url-access=subscription }}</ref><ref>{{Cite journal |last1=Licht |first1=Stuart |last2=Naschitz |first2=Vera |last3=Halperin |first3=Leonid |last4=Halperin |first4=Nadezhda |last5=Lin |first5=Lin |last6=Chen |first6=Jianjun |last7=Ghosh |first7=Susanta |last8=Liu |first8=Bing |date=2001-10-15 |title=Analysis of ferrate(VI) compounds and super-iron Fe(VI) battery cathodes: FTIR, ICP, titrimetric, XRD, UV/VIS, and electrochemical characterization |url=https://www.sciencedirect.com/science/article/pii/S0378775301007868 |journal=Journal of Power Sources |volume=101 |issue=2 |pages=167–176 |doi=10.1016/S0378-7753(01)00786-8 |bibcode=2001JPS...101..167L |issn=0378-7753|url-access=subscription }}</ref>
==References== {{reflist}}
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Category:Iron compounds Category:Anions Category:Ferrates