ferrate
Ferrate loosely refers to a material that can be viewed as containing anionic iron complexes. Examples include tetrachloroferrate ([FeCl4]2−), oxyanions (Ferrate(VI)), tetracarbonylferrate ([Fe(CO)4]2−), the organoferrates.{{Greenwood&Earnshaw2nd}}{{Page needed|date=March 2020}} The term ferrate derives {{etymology|la|ferrum|iron}}. Some ferrates are called super-iron by some and have uses in battery applications and as an oxidizer.{{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 }}{{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 }}{{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 |issn=1093-0191|url-access=subscription }} It can be used to clean water safely from a wide range of pollutants, including viruses, microbes, arsenic, sulfur-containing compounds, cyanides and other nitrogen-containing contaminants, many organic compounds, and algae.{{Cite journal |last=Licht |first=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 |issn=0013-936X|url-access=subscription }}
File:Disodium tetracarbonylferrate.png|Disodium salt of tetracarbonylferrate
File:Ferrate ion.svg|Structure of ferrate(VI), [FeO4]2−
File:1-Butyl-3-methylimidazolium tetrachloroferrate.svg|1-Butyl-3-methylimidazolium salt of [FeCl4]−
File:Potassium-trioxalatoferrate(III)-2D.png|Potassium tris(oxalato)ferrate