Editing Vanadium

{{about|the chemical element}}
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{{Use dmy dates|date=January 2022}}
{{Infobox vanadium}}

'''Vanadium''' is a [[chemical element]]; it has [[Symbol (chemistry)|symbol]] '''V''' and [[atomic number]] 23. It is a hard, silvery-grey, [[malleable]] [[transition metal]]. The elemental metal is rarely found in nature, but once isolated artificially, the formation of an [[oxide]] layer ([[passivation (chemistry)|passivation]]) somewhat stabilizes the free metal against further [[oxidation]].

[[Spain|Spanish]]-[[Mexico|Mexican]] scientist [[Andrés Manuel del Río]] discovered compounds of vanadium in 1801 by analyzing a new [[lead]]-bearing mineral he called "brown lead". Though he initially presumed its qualities were due to the presence of a new element, he was later erroneously convinced by French chemist [[Hippolyte Victor Collet-Descotils]] that the element was just [[chromium]]. Then in 1830, [[Nils Gabriel Sefström]] generated [[chlorides]] of vanadium, thus proving there was a new element, and named it "vanadium" after the Scandinavian goddess of beauty and fertility, [[Vanadís]] (Freyja). The name was based on the wide range of colors found in vanadium compounds. Del Río's lead mineral was ultimately named [[vanadinite]] for its vanadium content. In 1867, [[Henry Enfield Roscoe]] obtained the pure element.

Vanadium occurs naturally in about 65 [[mineral]]s and [[fossil fuel]] deposits. It is produced in [[China]] and [[Russia]] from steel smelter [[slag]]. Other countries produce it either from [[magnetite]] directly, flue dust of heavy oil, or as a byproduct of [[uranium]] mining. It is mainly used to produce specialty [[steel]] [[alloy]]s such as [[high-speed steel|high-speed tool steels]], and some [[aluminium alloy]]s. The most important industrial vanadium compound, [[vanadium(V) oxide|vanadium pentoxide]], is used as a catalyst for the production of [[sulfuric acid]]. The [[vanadium redox battery]] for energy storage may be an important application in the future.

Large amounts of vanadium [[ions]] are found in a few organisms, possibly as a [[toxin]]. The oxide and some other salts of vanadium have moderate toxicity. Particularly in the ocean, vanadium is used by some life forms as an active center of [[enzyme]]s, such as the [[vanadium bromoperoxidase]] of some ocean [[algae]].

== History ==
Vanadium was [[discovery of the chemical elements|discovered]] in Mexico in 1801 by the Spanish mineralogist [[Andrés Manuel del Río]]. Del Río extracted the element from a sample of Mexican "brown lead" ore, later named [[vanadinite]]. He found that its salts exhibit a wide variety of colors, and as a result, he named the element ''panchromium'' (Greek: παγχρώμιο "all colors"). Later, del Río renamed the element ''erythronium'' (Greek: ερυθρός "red") because most of the salts turned red upon heating. In 1805, French chemist [[Hippolyte Victor Collet-Descotils]], backed by del Río's friend Baron [[Alexander von Humboldt]], incorrectly declared that del Río's new element was an impure sample of [[chromium]]. Del Río accepted Collet-Descotils' statement and retracted his claim.<ref name="Cintas">{{cite journal |last1=Cintas |first1=Pedro |date=12 November 2004 |title=The Road to Chemical Names and Eponyms: Discovery, Priority, and Credit |journal=Angewandte Chemie International Edition |volume=43 |issue=44 |pages=5888–5894 |doi=10.1002/anie.200330074 |pmid=15376297}}</ref>

In 1831 Swedish chemist [[Nils Gabriel Sefström]] rediscovered the element in a new oxide he found while working with [[iron ore]]s. Later that year, [[Friedrich Wöhler]] confirmed that this element was identical to that found by del Río and hence confirmed del Río's earlier work.<ref name="sefs">{{cite journal |last=Sefström |first=N. G. |date=1831 |title=Ueber das Vanadin, ein neues Metall, gefunden im Stangeneisen von Eckersholm, einer Eisenhütte, die ihr Erz von Taberg in Småland bezieht |url=https://zenodo.org/record/1423544 |url-status=live |journal=[[Annalen der Physik und Chemie]] |volume=97 |issue=1 |pages=43–49 |bibcode=1831AnP....97...43S |doi=10.1002/andp.18310970103 |archive-url=https://web.archive.org/web/20210910010050/https://zenodo.org/record/1423544 |archive-date=10 September 2021 |access-date=27 August 2019}}</ref> Sefström chose a name beginning with V, which had not yet been assigned to any element. He called the element ''vanadium'' after [[Old Norse]] ''[[Freyja|Vanadís]]'' (another name for the [[Norse mythology|Norse]] [[Vanir]] goddess [[Freyja]], whose attributes include beauty and fertility), because of the many beautifully colored [[chemical compound]]s it produces.<ref name="sefs" /> On learning of Wöhler's findings, del Río began to passionately argue that his old claim be recognized, but the element kept the name ''vanadium''.<ref name="vanadium3">{{cite web |last1=Marshall |first1=James L. |last2=Marshall |first2=Virginia R. |date=2004 |title=Rediscovery of the Elements: The "Undiscovery" of Vanadium |url=https://digital.library.unt.edu/ark:/67531/metadc111200/m2/1/high_res_d/metadc111200.pdf |url-status=live |archive-url=https://web.archive.org/web/20230330044956/https://digital.library.unt.edu/ark:/67531/metadc111200/m2/1/high_res_d/metadc111200.pdf |archive-date=30 March 2023 |access-date= |website=unt.edu |publisher=The Hexagon |page=45 |quote=}}</ref> In 1831, the geologist [[George William Featherstonhaugh]] suggested that vanadium should be renamed "''rionium''" after del Río, but this suggestion was not followed.<ref>{{cite journal |last=Featherstonhaugh |first=George William |year=1831 |title=New Metal, provisionally called Vanadium |url=https://archive.org/stream/monthlyamericanj11831phil#page/68/mode/2up/search/rionium |journal=The Monthly American Journal of Geology and Natural Science |page=69}}</ref><!--Featherstonhaugh, the editor of the journal cited, comments on a letter from Berzelius to [[Pierre Louis Dulong]]-->

[[File:1910Ford-T.jpg|thumb|left|The [[Model T]] used vanadium steel in its [[chassis]].]]
As vanadium is usually found combined with other elements, the isolation of vanadium metal was difficult.<ref>{{cite journal |last1=Habashi |first1=Fathi |date=January 2001 |title=Historical Introduction to Refractory Metals |journal=Mineral Processing and Extractive Metallurgy Review |volume=22 |issue=1 |pages=25–53 |bibcode=2001MPEMR..22...25H |doi=10.1080/08827509808962488 |s2cid=100370649}}</ref> In 1831, [[Jöns Jakob Berzelius|Berzelius]] reported the production of the metal, but [[Henry Enfield Roscoe]] showed that Berzelius had produced the nitride, [[vanadium nitride]] (VN). Roscoe eventually produced the metal in 1867 by reduction of [[vanadium(II) chloride]], VCl<sub>2</sub>, with [[hydrogen]].<ref name="Roscoe">{{cite journal |date=31 December 1870 |title=XIX. Researches on vanadium |url=https://zenodo.org/record/1432055 |url-status=live |journal=Proceedings of the Royal Society of London |volume=18 |issue=114–122 |pages=37–42 |doi=10.1098/rspl.1869.0012 |s2cid=104146966 |archive-url=https://web.archive.org/web/20210909211727/https://zenodo.org/record/1432055 |archive-date=9 September 2021 |access-date=27 August 2019}}</ref> In 1927, pure vanadium was produced by reducing [[vanadium pentoxide]] with [[calcium]].<ref name="Marden">{{cite journal |last1=Marden |first1=J. W. |last2=Rich |first2=M. N. |date=July 1927 |title=Vanadium 1 |journal=Industrial & Engineering Chemistry |volume=19 |issue=7 |pages=786–788 |doi=10.1021/ie50211a012}}</ref>

The first large-scale industrial use of vanadium was in the [[steel]] alloy chassis of the [[Ford Model T]], inspired by French race cars. Vanadium steel allowed reduced weight while increasing [[tensile strength]] ({{circa|1905}}).<ref>{{cite book |last=Betz |first=Frederick |url=https://books.google.com/books?id=KnpGtu-R77UC&pg=PA158 |title=Managing Technological Innovation: Competitive Advantage from Change |date=2003 |publisher=Wiley-IEEE |isbn=978-0-471-22563-8 |pages=158–159}}</ref> For the first decade of the 20th century, most vanadium ore were mined by the [[American Vanadium Company]] from the [[Minas Ragra]] in Peru. Later, the demand for uranium rose, leading to increased mining of that metal's ores. One major uranium ore was [[carnotite]], which also contains vanadium. Thus, vanadium became available as a by-product of uranium production. Eventually, uranium mining began to supply a large share of the demand for vanadium.<ref name="Busch1961">{{cite book |last1=Busch |first1=Phillip Maxwell |url=http://digital.library.unt.edu/ark:/67531/metadc170746/ |title=Vanadium: A Materials Survey |date=1961 |publisher=U.S. Department of the Interior, Bureau of Mines |page=65 |oclc=934517147 |access-date=19 April 2023 |archive-url=https://web.archive.org/web/20230423075450/https://digital.library.unt.edu/ark:/67531/metadc170746/ |archive-date=23 April 2023 |url-status=live}}</ref><ref>{{cite web |last=Wise |first=James M. |date=May 2018 |title=Remarkable folded dacitic dikes at Mina Ragra, Peru |url=https://www.southamericatotheworld.com/remarkable-folded-dacitic-dikes-at-mina-ragra-peru/ |url-status=live |archive-url=https://web.archive.org/web/20210910012241/https://www.southamericatotheworld.com/remarkable-folded-dacitic-dikes-at-mina-ragra-peru/ |archive-date=10 September 2021 |access-date=21 November 2018}}</ref>

In 1911, German chemist [[Friedrich Wolfgang Martin Henze|Martin Henze]] discovered vanadium in the [[hemovanadin]] proteins found in [[blood cell]]s (or [[coelom]]ic cells) of [[Ascidiacea]] (sea squirts).<ref>{{cite journal |last=Henze |first=M. |author-link=Friedrich Wolfgang Martin Henze |date=1911 |title=Untersuchungen über das Blut der Ascidien. I. Mitteilung |url=https://books.google.com/books?id=x5g8AAAAIAAJ |journal=Z. Physiol. Chem. |volume=72 |issue=5–6 |pages=494–50 |doi=10.1515/bchm2.1911.72.5-6.494}}</ref><ref name="michibata2002">{{cite journal |last1=Michibata |first1=H. |last2=Uyama |first2=T. |last3=Ueki |first3=T. |last4=Kanamori |first4=K. |date=2002 |title=Vanadocytes, cells hold the key to resolving the highly selective accumulation and reduction of vanadium in ascidians |url=http://ir.lib.hiroshima-u.ac.jp/files/public/0/22/20141016115442843522/MicroscopResTech_56_421-434_2002.pdf |url-status=live |journal=Microscopy Research and Technique |volume=56 |issue=6 |pages=421–434 |doi=10.1002/jemt.10042 |pmid=11921344 |s2cid=15127292 |archive-url=https://web.archive.org/web/20200317132408/https://ir.lib.hiroshima-u.ac.jp/files/public/0/22/20141016115442843522/MicroscopResTech_56_421-434_2002.pdf |archive-date=17 March 2020 |access-date=27 August 2019}}</ref>

== Characteristics ==
[[File:Vanadium-bar.jpg|thumb|Polycrystalline high-purity (99.95%) vanadium cuboids, [[electron beam technology|ebeam remelted]] and macro-etched]]
Vanadium is an average-hard, [[ductility|ductile]], steel-blue metal. Vanadium is usually described as "soft", because it is ductile, [[malleable]], and not [[brittle]].<ref>{{cite book |author=George F. Vander Voort |url=https://books.google.com/books?id=GRQC8zYqtBIC&pg=PA137 |title=Metallography, principles and practice |date=1984 |publisher=ASM International |isbn=978-0-87170-672-0 |pages=137– |access-date=17 September 2011}}</ref><ref>{{cite book |last=Cardarelli |first=François |url=https://books.google.com/books?id=PvU-qbQJq7IC&pg=PA338 |title=Materials handbook: a concise desktop reference |date=2008 |publisher=Springer |isbn=978-1-84628-668-1 |pages=338– |access-date=17 September 2011}}</ref> Vanadium is harder than most metals and steels (see [[Hardnesses of the elements (data page)]] and [[iron#Mechanical properties|iron]]). It has good resistance to [[corrosion]] and it is stable against [[alkali]]s and [[sulfuric acid|sulfuric]] and [[hydrochloric acid]]s.<ref name="HollemanAF">{{cite book |last=Holleman |first=Arnold F. |title=Lehrbuch der Anorganischen Chemie |author2=Wiberg, Egon |author3=Wiberg, Nils |date=1985 |publisher=Walter de Gruyter |isbn=978-3-11-007511-3 |edition=91–100 |pages=1071–1075 |language=de |chapter=Vanadium}}</ref> It is [[oxidation|oxidized]] in air at about 933&nbsp;[[Kelvin|K]] (660&nbsp;°C, 1220&nbsp;°F), although an oxide [[passivation (chemistry)|passivation]] layer forms even at room temperature.<ref>{{Cite journal |last1=Klinser |first1=Gregor |last2=Zettl |first2=Roman |last3=Wilkening |first3=Martin |last4=Krenn |first4=Heinz |last5=Hanzu |first5=Ilie |last6=Würschum |first6=Roland |date=2019 |title=Redox processes in sodium vanadium phosphate cathodes – insights from operando magnetometry |journal=Physical Chemistry Chemical Physics |language=en |volume=21 |issue=36 |pages=20151–20155 |doi=10.1039/C9CP04045E |issn=1463-9076|doi-access=free |pmid=31482877 |bibcode=2019PCCP...2120151K }}</ref> It also reacts with hydrogen peroxide.

=== Isotopes ===
{{Main|Isotopes of vanadium}}

Naturally occurring vanadium is composed of one stable [[isotope]], <sup>51</sup>V, and one radioactive isotope, <sup>50</sup>V. The latter has a [[half-life]] of 2.71×10<sup>17</sup> years and a natural abundance of 0.25%. <sup>51</sup>V has a [[nuclear spin]] of {{frac|7|2}}, which is useful for [[Vanadium-51 nuclear magnetic resonance|NMR spectroscopy]].<ref name="Rehder">{{cite book |last1=Rehder |first1=D. |title=Vanadium-51 NMR |last2=Polenova |first2=T. |last3=Bühl |first3=M. |year=2007 |isbn=978-0-12-373919-3 |series=Annual Reports on NMR Spectroscopy |volume=62 |pages=49–114 |doi=10.1016/S0066-4103(07)62002-X}}</ref> Twenty-four artificial [[radioisotope]]s have been characterized, ranging in [[mass number]] from 40 to 65. The most stable of these isotopes are <sup>49</sup>V with a half-life of 330 days, and <sup>48</sup>V with a half-life of 16.0 days. The remaining [[radioactive]] isotopes have half-lives shorter than an hour, most below 10 seconds. At least four isotopes have [[nuclear isomer|metastable excited states]].<ref>{{NUBASE 2003}}</ref> [[Electron capture]] is the main [[decay mode]] for isotopes lighter than <sup>51</sup>V. For the heavier ones, the most common mode is [[beta decay]].{{NUBASE2020|ref}} The electron capture reactions lead to the formation of element 22 ([[titanium]]) isotopes, while beta decay leads to element 24 ([[chromium]]) isotopes.

== Compounds ==
{{Main|Vanadium compounds}}
[[File:Vanadiumoxidationstates.jpg|thumb|left|upright|From left: [V(H<sub>2</sub>O)<sub>6</sub>]<sup>2+</sup> (lilac), [V(H<sub>2</sub>O)<sub>6</sub>]<sup>3+</sup> (green), [VO(H<sub>2</sub>O)<sub>5</sub>]<sup>2+</sup> (blue) and [VO(H<sub>2</sub>O)<sub>5</sub>]<sup>3+</sup> (yellow)]]
The chemistry of vanadium is noteworthy for the accessibility of the four adjacent [[oxidation state]]s 2–5. In an [[metal ions in aqueous solution|aqueous solution]], vanadium forms [[metal aquo complex]]es of which the colors are lilac [V(H<sub>2</sub>O)<sub>6</sub>]<sup>2+</sup>, green [V(H<sub>2</sub>O)<sub>6</sub>]<sup>3+</sup>, blue [VO(H<sub>2</sub>O)<sub>5</sub>]<sup>2+</sup>, yellow-orange oxides [VO(H<sub>2</sub>O)<sub>5</sub>]<sup>3+</sup>, the formula for which depends on pH. Vanadium(II) compounds are reducing agents, and vanadium(V) compounds are oxidizing agents. Vanadium(IV) compounds often exist as [[vanadyl ion|vanadyl]] derivatives, which contain the VO<sup>2+</sup> center.<ref name="HollemanAF" />

[[Ammonium metavanadate|Ammonium vanadate(V)]] (NH<sub>4</sub>VO<sub>3</sub>) can be successively reduced with elemental [[zinc]] to obtain the different colors of vanadium in these four oxidation states. Lower oxidation states occur in compounds such as [[vanadium hexacarbonyl|V(CO)<sub>6</sub>]], {{chem|[V(CO)|6|]|-}} and substituted derivatives.<ref name="HollemanAF" />

[[Vanadium(V) oxide|Vanadium pentoxide]] is a commercially important catalyst for the production of sulfuric acid, a reaction that exploits the ability of vanadium oxides to undergo redox reactions.<ref name="HollemanAF" />

The [[vanadium redox battery]] utilizes all four oxidation states: one electrode uses the +5/+4 couple and the other uses the +3/+2 couple. Conversion of these oxidation states is illustrated by the reduction of a strongly acidic solution of a vanadium(V) compound with zinc dust or amalgam. The initial yellow color characteristic of the pervanadyl ion [VO<sub>2</sub>(H<sub>2</sub>O)<sub>4</sub>]<sup>+</sup> is replaced by the blue color of [VO(H<sub>2</sub>O)<sub>5</sub>]<sup>2+</sup>, followed by the green color of [V(H<sub>2</sub>O)<sub>6</sub>]<sup>3+</sup> and then the violet color of [V(H<sub>2</sub>O)<sub>6</sub>]<sup>2+</sup>.<ref name="HollemanAF" /> Another potential vanadium battery based on VB<sub>2</sub> uses multiple oxidation state to allow for 11 electrons to be released per VB<sub>2</sub>, giving it higher energy capacity by order of compared to Li-ion and gasoline per unit volume.<ref name=":0">{{Cite journal |last1=Licht |first1=Stuart |last2=Wu |first2=Huiming |last3=Yu |first3=Xingwen |last4=Wang |first4=Yufei |date=2008-07-11 |title=Renewable highest capacity VB2/air energy storage |url=https://pubs.rsc.org/en/content/articlelanding/2008/cc/b807929c |journal=Chemical Communications |language=en |issue=28 |pages=3257–3259 |doi=10.1039/B807929C |pmid=18622436 |issn=1364-548X}}</ref> VB<sub>2</sub> batteries can be further enhanced as air batteries, allowing for even higher energy density and lower weight than lithium battery or gasoline, even though recharging remains a challenge. <ref name=":0" />

=== Oxyanions ===
[[File:decavanadate polyhedra.png|thumb|The [[decavanadate]] structure]]
<!-- [[File:Ammonium-metavanadate-chains-3D.png|thumb|upright|Metavanadate chains]] -->In an aqueous solution, vanadium(V) forms an extensive family of [[oxyanion]]s as established by [[Vanadium-51 nuclear magnetic resonance|<sup>51</sup>V NMR spectroscopy]].<ref name="Rehder" /> The interrelationships in this family are described by the [[predominance diagram]], which shows at least 11 species, depending on pH and concentration.<ref>{{Greenwood&Earnshaw|page=984}}</ref> The tetrahedral orthovanadate ion, {{chem|VO|4|3−}}, is the principal species present at pH 12–14. Similar in size and charge to phosphorus(V), vanadium(V) also parallels its chemistry and crystallography. [[Sodium orthovanadate|Orthovanadate]] V{{chem|O|4|3−}} is used in [[protein crystallography]]<ref>{{cite journal |last1=Sinning |first1=Irmgard |last2=Hol |first2=Wim G. J. |date=2004 |title=The power of vanadate in crystallographic investigations of phosphoryl transfer enzymes |journal=FEBS Letters |volume=577 |issue=3 |pages=315–21 |doi=10.1016/j.febslet.2004.10.022 |pmid=15556602 |s2cid=8328704 |doi-access=free|bibcode=2004FEBSL.577..315D }}</ref> to study the [[biochemistry]] of phosphate.<ref>{{cite journal |last1=Seargeant |first1=L E |last2=Stinson |first2=R A |date=1 July 1979 |title=Inhibition of human alkaline phosphatases by vanadate |journal=Biochemical Journal |volume=181 |issue=1 |pages=247–250 |doi=10.1042/bj1810247 |pmc=1161148 |pmid=486156}}</ref> Besides that, this anion also has been shown to interact with the activity of some specific enzymes.<ref>{{cite journal |last1=Crans |first1=Debbie C. |last2=Simone |first2=Carmen M. |date=9 July 1991 |title=Nonreductive interaction of vanadate with an enzyme containing a thiol group in the active site: glycerol-3-phosphate dehydrogenase |journal=Biochemistry |volume=30 |issue=27 |pages=6734–6741 |doi=10.1021/bi00241a015 |pmid=2065057}}</ref><ref>{{cite journal |last1=Karlish |first1=S. J. D. |last2=Beaugé |first2=L. A. |last3=Glynn |first3=I. M. |date=November 1979 |title=Vanadate inhibits (Na+ + K+)ATPase by blocking a conformational change of the unphosphorylated form |journal=Nature |volume=282 |issue=5736 |pages=333–335 |bibcode=1979Natur.282..333K |doi=10.1038/282333a0 |pmid=228199 |s2cid=4341480}}</ref> The tetrathiovanadate [VS<sub>4</sub>]<sup>3−</sup> is analogous to the orthovanadate ion.<ref>{{Greenwood&Earnshaw|page=988}}</ref>

At lower pH values, the monomer [HVO<sub>4</sub>]<sup>2−</sup> and dimer [V<sub>2</sub>O<sub>7</sub>]<sup>4−</sup> are formed, with the monomer predominant at a vanadium concentration of less than c. 10<sup>−2</sup>M (pV > 2, where pV is equal to the minus value of the logarithm of the total vanadium concentration/M). The formation of the divanadate ion is analogous to the formation of the [[dichromate]] ion.<ref>{{cite journal |last1=Crans |first1=Debbie C. |date=18 December 2015 |title=Antidiabetic, Chemical, and Physical Properties of Organic Vanadates as Presumed Transition-State Inhibitors for Phosphatases |journal=The Journal of Organic Chemistry |volume=80 |issue=24 |pages=11899–11915 |doi=10.1021/acs.joc.5b02229 |pmid=26544762|doi-access=free }}</ref><ref>{{cite thesis |last1=Jung |first1=Sabrina |title=Speciation of molybdenum- and vanadium-based polyoxometalate species in aqueous medium and gas-phase and its consequences for M1 structured MoV oxide synthesis |date=2018 |doi=10.14279/depositonce-7254}}</ref> As the pH is reduced, further protonation and condensation to [[vanadate|polyvanadates]] occur: at pH 4–6 [H<sub>2</sub>VO<sub>4</sub>]<sup>−</sup> is predominant at pV greater than ca. 4, while at higher concentrations trimers and tetramers are formed.<ref>{{Citation |last=Cruywagen |first=J. J. |title=Protonation, Oligomerization, and Condensation Reactions of Vanadate(V), Molybdate(vi), and Tungstate(vi) |date=1999-01-01 |url=https://www.sciencedirect.com/science/article/pii/S0898883808602706 |volume=49 |pages=127–182 |editor-last=Sykes |editor-first=A. G. |access-date=2023-04-16 |series=Advances in Inorganic Chemistry |publisher=Academic Press |language=en |doi=10.1016/S0898-8838(08)60270-6 |isbn=978-0-12-023649-7}}</ref> Between pH 2–4 [[decavanadate]] predominates, its formation from orthovanadate is represented by this condensation reaction:
:10 [VO<sub>4</sub>]<sup>3−</sup> + 24 H<sup>+</sup> → [V<sub>10</sub>O<sub>28</sub>]<sup>6−</sup> + 12 H<sub>2</sub>O

[[File:Vanadium crystal.jpg|thumb|Vanadium crystal]]
In decavanadate, each V(V) center is surrounded by six oxide [[ligand]]s.<ref name="HollemanAF" /> Vanadic acid, H<sub>3</sub>VO<sub>4</sub>, exists only at very low concentrations because protonation of the tetrahedral species [H<sub>2</sub>VO<sub>4</sub>]<sup>−</sup> results in the preferential formation of the octahedral [VO<sub>2</sub>(H<sub>2</sub>O)<sub>4</sub>]<sup>+</sup> species.<ref>{{Cite book |last1=Tracey |first1=Alan S. |url=https://books.google.com/books?id=vkMGP3PiuyYC&dq=+protonation+of+the+tetrahedral+species+%5BH2VO4%5D%E2%88%92+results+in+the+preferential+formation+of+the+octahedral+%5BVO2(H2O)4%5D++species&pg=PP1 |title=Vanadium: Chemistry, Biochemistry, Pharmacology and Practical Applications |last2=Willsky |first2=Gail R. |last3=Takeuchi |first3=Esther S. |date=2007-03-19 |publisher=CRC Press |isbn=978-1-4200-4614-4 |language=en}}</ref> In strongly acidic solutions, pH&nbsp;<&nbsp;2, [VO<sub>2</sub>(H<sub>2</sub>O)<sub>4</sub>]<sup>+</sup> is the predominant species, while the oxide V<sub>2</sub>O<sub>5</sub> precipitates from solution at high concentrations. The oxide is formally the [[acidic oxide|acid anhydride]] of vanadic acid. The structures of many [[vanadate]] compounds have been determined by X-ray crystallography.

[[File:VinwaterPourbaixdiagram2.svg|thumb|The [[Pourbaix diagram]] for vanadium in water, which shows the [[redox]] potentials between various vanadium species in different oxidation states<ref>{{cite journal |last1=Al-Kharafi |first1=F.M. |last2=Badawy |first2=W.A. |date=January 1997 |title=Electrochemical behaviour of vanadium in aqueous solutions of different pH |journal=Electrochimica Acta |volume=42 |issue=4 |pages=579–586 |doi=10.1016/S0013-4686(96)00202-2}}</ref>]]

Vanadium(V) forms various peroxo complexes, most notably in the active site of the vanadium-containing [[bromoperoxidase]] enzymes. The species VO(O<sub>2</sub>)(H<sub>2</sub>O)<sub>4</sub><sup>+</sup> is stable in acidic solutions. In alkaline solutions, species with 2, 3 and 4 peroxide groups are known; the last forms violet salts with the formula M<sub>3</sub>V(O<sub>2</sub>)<sub>4</sub> nH<sub>2</sub>O (M= Li, Na, etc.), in which the vanadium has an 8-coordinate dodecahedral structure.<ref>{{Greenwood&Earnshaw}}, p994.</ref><ref>{{cite book |author=Strukul, Giorgio |url=https://books.google.com/books?id=Lmt3x9CyfLgC&pg=PA128 |title=Catalytic oxidations with hydrogen peroxide as oxidant |date=1992 |publisher=Springer |isbn=978-0-7923-1771-5 |page=128}}</ref>

=== Halide derivatives ===
Twelve binary [[halides]], compounds with the formula VX<sub>n</sub> (n=2..5), are known.<ref name="G&E989">{{Greenwood&Earnshaw2nd|page=989}}</ref> VI<sub>4</sub>, VCl<sub>5</sub>, VBr<sub>5</sub>, and VI<sub>5</sub> do not exist or are extremely unstable. In combination with other reagents, [[vanadium(IV) chloride|VCl<sub>4</sub>]] is used as a catalyst for the polymerization of [[diene]]s. Like all binary halides, those of vanadium are [[Lewis acid]]ic, especially those of V(IV) and V(V).<ref name="G&E989" /> Many of the halides form octahedral complexes with the formula VX<sub>''n''</sub>L<sub>6−''n''</sub> (X= halide; L= other ligand).

Many vanadium [[oxyhalide]]s (formula VO<sub>m</sub>X<sub>n</sub>) are known.<ref>{{Greenwood&Earnshaw|page=993}}</ref> The oxytrichloride and oxytrifluoride ([[vanadium oxytrichloride|VOCl<sub>3</sub>]] and [[Vanadium(V) oxytrifluoride|VOF<sub>3</sub>]]) are the most widely studied. Akin to POCl<sub>3</sub>, they are volatile,<ref>{{cite journal |last1=Flesch |first1=Gerald D. |last2=Svec |first2=Harry J. |date=1 August 1975 |title=Thermochemistry of vanadium oxytrichloride and vanadium oxytrifluoride by mass spectrometry |journal=Inorganic Chemistry |volume=14 |issue=8 |pages=1817–1822 |doi=10.1021/ic50150a015}}</ref> adopt tetrahedral structures in the gas phase, and are Lewis acidic.<ref>{{cite journal |last1=Iqbal |first1=Javed |last2=Bhatia |first2=Beena |last3=Nayyar |first3=Naresh K. |date=March 1994 |title=Transition Metal-Promoted Free-Radical Reactions in Organic Synthesis: The Formation of Carbon-Carbon Bonds |journal=Chemical Reviews |volume=94 |issue=2 |pages=519–564 |doi=10.1021/cr00026a008}}</ref>

=== Coordination compounds ===
[[File:Vanadyl-acetylacetonate-from-xtal-3D-balls.png|thumb|A [[ball-and-stick model]] of [[vanadyl acetylacetonate|VO(O<sub>2</sub>C<sub>5</sub>H<sub>7</sub>)<sub>2</sub>]]]]
Complexes of vanadium(II) and (III) are reducing, while those of V(IV) and V(V) are oxidants. The vanadium ion is rather large and some complexes achieve coordination numbers greater than 6, as is the case in [V(CN)<sub>7</sub>]<sup>4−</sup>. Oxovanadium(V) also forms 7 coordinate coordination complexes with tetradentate ligands and peroxides and these complexes are used for oxidative brominations and thioether oxidations. The coordination chemistry of V<sup>4+</sup> is dominated by the [[vanadyl]] center, VO<sup>2+</sup>, which binds four other ligands strongly and one weakly (the one trans to the vanadyl center). An example is [[vanadyl acetylacetonate]] (V(O)(O<sub>2</sub>C<sub>5</sub>H<sub>7</sub>)<sub>2</sub>). In this complex, the vanadium is 5-coordinate, distorted square pyramidal, meaning that a sixth ligand, such as pyridine, may be attached, though the [[association constant]] of this process is small. Many 5-coordinate vanadyl complexes have a trigonal bipyramidal geometry, such as VOCl<sub>2</sub>(NMe<sub>3</sub>)<sub>2</sub>.<ref>{{Greenwood&Earnshaw2nd|page=995}}</ref> The coordination chemistry of V<sup>5+</sup> is dominated by the relatively stable dioxovanadium coordination complexes<ref>{{cite thesis |last1=Geiser |first1=Jan Nicholas |title=Development of an improved state-of-charge sensor for the all-vanadium redox flow battery |date=2019 |doi=10.22028/D291-29229}}</ref> which are often formed by aerial oxidation of the vanadium(IV) precursors indicating the stability of the +5 oxidation state and ease of interconversion between the +4 and +5 states.<ref>{{cite journal |last1=Nica |first1=Simona |last2=Rudolph |first2=Manfred |last3=Görls |first3=Helmar |last4=Plass |first4=Winfried |date=April 2007 |title=Structural characterization and electrochemical behavior of oxovanadium(V) complexes with N-salicylidene hydrazides |journal=Inorganica Chimica Acta |volume=360 |issue=5 |pages=1743–1752 |doi=10.1016/j.ica.2006.09.018}}</ref>

=== Organometallic compounds ===
{{Main|Organovanadium chemistry}}

The organometallic chemistry of vanadium is well{{en dash}}developed. [[Vanadocene dichloride]] is a versatile starting reagent and has applications in organic chemistry.<ref name="wilkinson">{{cite journal |last1=Wilkinson |first1=G. |last2=Birmingham |first2=J. M. |date=September 1954 |title=Bis-cyclopentadienyl Compounds of Ti, Zr, V, Nb and Ta |journal=Journal of the American Chemical Society |volume=76 |issue=17 |pages=4281–4284 |doi=10.1021/ja01646a008|bibcode=1954JAChS..76.4281W }}</ref> [[Vanadium carbonyl]], V(CO)<sub>6</sub>, is a rare example of a paramagnetic [[metal carbonyl]]. Reduction yields V{{chem|(CO)|6|−}} ([[isoelectronic]] with [[hexacarbonylchromium|Cr(CO)<sub>6</sub>]]), which may be further reduced with sodium in liquid ammonia to yield V{{chem|(CO)|5|3−}} (isoelectronic with Fe(CO)<sub>5</sub>).<ref>{{cite journal |last1=Bellard |first1=S. |last2=Rubinson |first2=K. A. |last3=Sheldrick |first3=G. M. |date=15 February 1979 |title=Crystal and molecular structure of vanadium hexacarbonyl |journal=Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry |volume=35 |issue=2 |pages=271–274 |doi=10.1107/S0567740879003332|bibcode=1979AcCrB..35..271B }}</ref><ref>{{cite book |last=Elschenbroich |first=C. |title=Organometallics: A Concise Introduction |author2=Salzer A. |date=1992 |publisher=Wiley-VCH |isbn=978-3-527-28165-7}}</ref>

== Occurrence ==
[[File:Vanadinite, goethite(2).jpg|thumb|[[Vanadinite]]]]
Metallic vanadium is rare in nature (known as '''native vanadium'''),<ref>{{cite journal |author1=Ostrooumov, M. |author2=Taran, Y. |year=2015 |title=Discovery of Native Vanadium, a New Mineral from the Colima Volcano, State of Colima (Mexico) |url=https://www.uhu.es/fexp/sem2015/arc/macla/macla_20_109-110.pdf |url-status=live |journal=Revista de la Sociedad Española de Mineralogía |volume=20 |pages=109–110 |archive-url=https://web.archive.org/web/20230207070847/https://www.uhu.es/fexp/sem2015/arc/macla/macla_20_109-110.pdf |archive-date=7 February 2023 |access-date=7 February 2023}}</ref><ref>{{cite web |title=Vanadium: Vanadium mineral information and data |url=https://www.mindat.org/min-43604.html |url-status=live |archive-url=https://web.archive.org/web/20210716205934/https://www.mindat.org/min-43604.html |archive-date=16 July 2021 |access-date=2016-03-02 |website=Mindat.org}}</ref> having been found among fumaroles of the [[Volcán de Colima|Colima Volcano]], but vanadium compounds occur naturally in about 65 different [[mineral]]s. 

Vanadium began to be used in the manufacture of special steels in 1896. At that time, very few deposits of vanadium ores were known. Between 1899 and 1906, the main deposits exploited were the mines of Santa Marta de los Barros (Badajoz), Spain. [[Vanadinite]] was extracted from these mines.<ref>{{Cite book |last=Calvo Rebollar |first=Miguel |title=Construyendo la Tabla Periódica |publisher=Prames |year=2019 |isbn=978-84-8321-908-9 |location=Zaragoza, Spain |pages=161–165 |language=es |trans-title=Building the Periodic Table}}</ref>  At the beginning of the 20th century, a large deposit of vanadium ore was discovered near Junín, [[Cerro de Pasco]], [[Peru]] (now the [[Minas Ragra]] vanadium mine).<ref>{{cite journal |last1=Hillebrand |first1=W. F. |year=1907 |title=The Vanadium Sulphide, Patronite, and ITS Mineral Associates from Minasragra, Peru |url=https://zenodo.org/record/1450154 |url-status=live |journal=Journal of the American Chemical Society |volume=29 |issue=7 |pages=1019–1029 |doi=10.1021/ja01961a006 |bibcode=1907JAChS..29.1019H |archive-url=https://web.archive.org/web/20210911093143/https://zenodo.org/record/1450154 |archive-date=11 September 2021 |access-date=6 September 2020}}</ref><ref>{{cite journal |last1=Hewett |first1=F. |year=1906 |title=A New Occurrence of Vanadium in Peru |journal=The Engineering and Mining Journal |volume=82 |issue=9 |pages=385}}</ref><ref name="scielo">{{cite journal |last1=Steinberg |first1=W.S. |last2=Geyser |first2=W. |last3=Nell |first3=J. |year=2011 |title=The history and development of the pyrometallurgical processes at Evraz Highveld Steel & Vanadium |url=http://www.scielo.org.za/pdf/jsaimm/v111n10/v111n10a09.pdf |url-status=live |journal=The Journal of the Southern African Institute of Mining and Metallurgy |volume=111 |pages=705–710 |archive-url=https://web.archive.org/web/20210911093146/http://www.scielo.org.za/pdf/jsaimm/v111n10/v111n10a09.pdf |archive-date=11 September 2021 |access-date=17 December 2018}}</ref> For several years this [[patrónite]] (VS<sub>4</sub>)<ref>{{cite web |title=mineralogical data about Patrónite |url=https://www.mindat.org/min-3131.html |url-status=live |archive-url=https://web.archive.org/web/20210430004309/https://www.mindat.org/min-3131.html |archive-date=30 April 2021 |access-date=19 January 2009 |publisher=mindata.org}}</ref> deposit was an economically significant source for vanadium ore. In 1920 roughly two-thirds of the worldwide production was supplied by the mine in Peru.<ref>{{cite journal |last1=Allen |first1=M. A. |last2=Butler |first2=G. M. |date=1921 |title=Vanadium |url=https://repository.arizona.edu/bitstream/handle/10150/630042/b-115_vanadium.pdf |url-status=live |journal=University of Arizona |archive-url=https://web.archive.org/web/20210427182032/https://repository.arizona.edu/bitstream/handle/10150/630042/b-115_vanadium.pdf |archive-date=27 April 2021 |access-date=20 January 2020}}</ref> With the production of uranium in the 1910s and 1920s from [[carnotite]] ({{nowrap|K<sub>2</sub>(UO<sub>2</sub>)<sub>2</sub>(VO<sub>4</sub>)<sub>2</sub>·3H<sub>2</sub>O}}) vanadium became available as a side product of uranium production. [[Vanadinite]] ({{nowrap|Pb<sub>5</sub>(VO<sub>4</sub>)<sub>3</sub>Cl}}) and other vanadium bearing minerals are only mined in exceptional cases. With the rising demand, much of the world's vanadium production is now sourced from vanadium-bearing [[magnetite]] found in [[ultramafic]] [[gabbro]] bodies. If this [[titanomagnetite]] is used to produce iron, most of the vanadium goes to the [[slag]] and is extracted from it.<ref>{{cite journal |last1=Hukkanen |first1=E. |last2=Walden |first2=H. |year=1985 |title=The production of vanadium and steel from titanomagnetites |journal=International Journal of Mineral Processing |volume=15 |issue=1–2 |pages=89–102 |bibcode=1985IJMP...15...89H |doi=10.1016/0301-7516(85)90026-2}}</ref><ref name="scielo" />

Vanadium is mined mostly in [[China]], [[South Africa]] and eastern [[Russia]]. In 2022 these three countries mined more than 96% of the 100,000 [[tonne|tons]] of produced vanadium, with China providing 70%.<ref name="usgs">{{cite web |last=Polyak |first=Désirée E. |title=Mineral Commodity Summaries 2023: Vanadium |url=https://pubs.usgs.gov/periodicals/mcs2023/mcs2023-vanadium.pdf |url-status=live |archive-url=https://web.archive.org/web/20230207070837/https://pubs.usgs.gov/periodicals/mcs2023/mcs2023-vanadium.pdf |archive-date=7 February 2023 |access-date=7 February 2023 |publisher=[[United States Geological Survey]]}}</ref>

Fumaroles of Colima are known of being vanadium-rich, depositing other vanadium minerals, that include shcherbinaite (V<sub>2</sub>O<sub>5</sub>) and [[colimaite]] (K<sub>3</sub>VS<sub>4</sub>).<ref>Ostrooumov, M., and Taran, Y., 2015. Discovery of Native Vanadium, a New Mineral from the Colima Volcano, State of Colima (Mexico). Revista de la Sociedad Española de Mineralogía 20, 109-110</ref><ref>{{cite web|url=http://www.mindat.org/min-43604.html |title=Vanadium: Vaandium mineral information and data |website=Mindat.org |accessdate=2016-03-02}}</ref><ref>{{cite web|url=http://www.mindat.org/min-43604.html |title=Colima volcano (Volcan de Fuego; Volcan de Colima), Colima volcanic complex, Jalisco, Mexico |website=Mindat.org |accessdate=2016-03-02}}</ref>

Vanadium is also present in [[bauxite]] and deposits of [[crude oil]], [[coal]], [[oil shale]], and [[tar sand]]s. In crude oil, concentrations up to 1200&nbsp;ppm have been reported. When such oil products are burned, traces of vanadium may cause [[corrosion]] in engines and boilers.<ref>{{cite journal |last1=Pearson |first1=C. D. |last2=Green |first2=J. B. |date=1 May 1993 |title=Vanadium and nickel complexes in petroleum resid acid, base, and neutral fractions |url=https://digital.library.unt.edu/ark:/67531/metadc1198139/ |url-status=live |journal=Energy & Fuels |volume=7 |issue=3 |pages=338–346 |doi=10.1021/ef00039a001 |archive-url=https://web.archive.org/web/20210911093151/https://digital.library.unt.edu/ark:/67531/metadc1198139/ |archive-date=11 September 2021 |access-date=10 August 2018}}</ref> An estimated 110,000 tons of vanadium per year are released into the atmosphere by burning [[fossil fuels]].<ref>{{cite journal |last1=Anke |first1=Manfred |date=2004 |title=Vanadium: An element both essential and toxic to plants, animals and humans? |url=https://analesranf.com/wp-content/uploads/2004/70_04/7004_06.pdf |url-status=live |journal=Anales de la Real Academia Nacional de Farmacia |volume=70 |issue=4 |pages=961–999 |archive-url=https://web.archive.org/web/20230419220209/https://analesranf.com/wp-content/uploads/2004/70_04/7004_06.pdf |archive-date=19 April 2023 |access-date=19 April 2023}}</ref> [[Black shale]]s are also a potential source of vanadium. During WWII some vanadium was extracted from [[alum shale]]s in the south of Sweden.<ref>{{cite book |last1=Dyni |first1=John R. |title=Scientific Investigations Report |year=2006 |page=22 |chapter=Geology and resources of some world oil-shale deposits |doi=10.3133/sir29955294 |s2cid=19814608}}</ref>

In the universe, the [[Abundance of the chemical elements#Universe|cosmic abundance]] of vanadium is 0.0001%, making the element nearly as common as [[copper]] or [[zinc]].<ref name="Dieter">{{cite book |last1=Rehder |first1=Dieter |title=Bioinorganic Vanadium Chemistry |date=2008 |publisher=John Wiley & Sons, Ltd |isbn=978-0-470-06509-9 |edition=1st |series=Inorganic Chemistry |location=Hamburg, Germany |pages=5 & 9–10 |doi=10.1002/9780470994429}}</ref> Vanadium is the 19th most abundant element in the crust.<ref>{{Cite book |last=Emsley |first=John |url=https://books.google.com/books?id=j-Xu07p3cKwC&dq=%2219th+most+abundant+element%22&pg=PA486 |title=Nature's Building Blocks: An A-Z Guide to the Elements |date=2003 |publisher=Oxford University Press |isbn=978-0-19-850340-8 |language=en}}</ref> It is detected [[Optical spectrometer|spectroscopically]] in light from the [[Sun]] and sometimes in the light from other [[star]]s.<ref>{{cite journal |last1=Cowley |first1=C. R. |last2=Elste |first2=G. H. |last3=Urbanski |first3=J. L. |date=October 1978 |title=Vanadium abundances in early A stars |journal=Publications of the Astronomical Society of the Pacific |volume=90 |pages=536 |bibcode=1978PASP...90..536C |doi=10.1086/130379 |s2cid=121428891|doi-access=free }}</ref> The [[vanadyl ion]] is also abundant in [[seawater]], having an average concentration of 30&nbsp;[[Molar concentration#Units|nM]] (1.5&nbsp;mg/m<sup>3</sup>).<ref name="Dieter" /> Some [[mineral water]] [[spring (hydrology)|springs]] also contain the ion in high concentrations. For example, springs near [[Mount Fuji]] contain as much as 54&nbsp;[[microgram|μg]] per [[liter]].<ref name="Dieter" />

== Production ==
[[File:Vanadium-production(en).svg|thumb|Vanadium production trend]]
[[File:Vanadium crystal vakuum sublimed.jpg|thumb|left|Vacuum sublimed vanadium [[dendrite (crystal)|dendritic]] crystals (99.9%)]]

Vanadium metal is obtained by a multistep process that begins with roasting crushed ore with [[sodium chloride|NaCl]] or [[sodium carbonate|Na<sub>2</sub>CO<sub>3</sub>]] at about 850&nbsp;°C to give [[sodium metavanadate]] (NaVO<sub>3</sub>). An aqueous extract of this solid is acidified to produce "red cake", a polyvanadate salt, which is reduced with [[calcium]] metal. As an alternative for small-scale production, vanadium pentoxide is reduced with [[hydrogen]] or [[magnesium]]. Many other methods are also used, in all of which vanadium is produced as a [[byproduct]] of other processes.<ref name="Moskalyk">{{cite journal |last1=Moskalyk |first1=R.R |last2=Alfantazi |first2=A.M |date=September 2003 |title=Processing of vanadium: a review |journal=Minerals Engineering |volume=16 |issue=9 |pages=793–805 |bibcode=2003MiEng..16..793M |doi=10.1016/S0892-6875(03)00213-9}}</ref> Purification of vanadium is possible by the [[crystal bar process]] developed by [[Anton Eduard van Arkel]] and [[Jan Hendrik de Boer]] in 1925. It involves the formation of the metal iodide, in this example [[vanadium(III) iodide]], and the subsequent decomposition to yield pure metal:<ref>{{cite journal |last1=Carlson |first1=O. N. |last2=Owen |first2=C. V. |date=1961 |title=Preparation of High-Purity Vanadium Metalb by the Iodide Refining Process |journal=Journal of the Electrochemical Society |volume=108 |issue=1 |pages=88 |doi=10.1149/1.2428019}}</ref>
:2 V + 3 I<sub>2</sub> {{eqm}} 2 VI<sub>3</sub>

[[File:FerroVanadium.jpg|thumb|Ferrovanadium chunks]]

Most vanadium is used as a [[steel]] alloy called [[ferrovanadium]]. Ferrovanadium is produced directly by reducing a mixture of vanadium oxide, iron oxides and iron in an electric furnace. The vanadium ends up in [[pig iron]] produced from vanadium-bearing magnetite. Depending on the ore used, the slag contains up to 25% of vanadium.<ref name="Moskalyk" />

== Applications ==
[[File:Knarre.jpg|thumb|upright|right|Tool made from vanadium steel]]

=== Alloys ===
Approximately 85% of the vanadium produced is used as [[ferrovanadium]] or as a [[steel]] additive.<ref name="Moskalyk" /> The considerable increase of strength in steel containing small amounts of vanadium was discovered in the early 20th century. Vanadium forms stable nitrides and carbides, resulting in a significant increase in the strength of steel.<ref name="Chandler">{{cite book |last=Chandler |first=Harry |url=https://books.google.com/books?id=arupok8PTBEC |title=Metallurgy for the Non-metallurgist |date=1998 |publisher=ASM International |isbn=978-0-87170-652-2 |pages=6–7}}</ref> From that time on, vanadium steel was used for applications in [[axle]]s, bicycle frames, [[crankshaft]]s, gears, and other critical components. There are two groups of vanadium steel alloys. Vanadium high-carbon steel alloys contain 0.15–0.25% vanadium, and [[High-speed steel|high-speed tool steels]] (HSS) have a vanadium content of 1–5%. For high-speed tool steels, a hardness above [[Rockwell hardness|HRC]] 60 can be achieved. HSS steel is used in [[surgical instrument]]s and [[tool]]s.<ref>{{cite book |last=Davis |first=Joseph R. |url=https://books.google.com/books?id=Kws7x68r_aUC&pg=PA11 |title=Tool Materials: Tool Materials |date=1995 |publisher=ASM International |isbn=978-0-87170-545-7}}</ref> [[Powder metallurgy|Powder-metallurgic]] alloys contain up to 18% percent vanadium. The high content of vanadium carbides in those alloys increases wear resistance significantly. One application for those alloys is tools and knives.<ref>{{cite book |author1=Oleg D. Neikov |url=https://books.google.com/books?id=6aP3te2hGuQC&pg=PA490 |title=Handbook of Non-Ferrous Metal Powders: Technologies and Applications |last2=Naboychenko |first2=Stanislav |last3=Mourachova |first3=Irina |author4=Victor G. Gopienko |author5=Irina V. Frishberg |author6=Dina V. Lotsko |date=2009-02-24 |isbn=978-0-08-055940-7 |page=490 | publisher=Elsevier |access-date=17 October 2013}}</ref><!--http://www.wujii.com.tw/PDF/CPM%2015V.pdf-->

Vanadium stabilizes the beta form of titanium and increases the strength and temperature stability of titanium. Mixed with [[aluminium]] in [[titanium]] alloys, it is used in [[jet engine]]s, high-speed airframes and [[dental implant]]s. The most common alloy for seamless tubing is [[titanium alloy#Grades of titanium|Titanium 3/2.5]] containing 2.5% vanadium, the titanium alloy of choice in the aerospace, defense, and bicycle industries.<ref>{{cite web |title=Technical Supplement: Titanium |url=http://www.sevencycles.com/buildingbike/techsupplement/ti.php |url-status=dead |archive-url=https://web.archive.org/web/20161103173648/http://www.sevencycles.com/buildingbike/techsupplement/ti.php |archive-date=3 November 2016 |access-date=1 November 2016 |website=Seven Cycles}}</ref> Another common alloy, primarily produced in sheets, is [[Titanium 6AL-4V]], a titanium alloy with 6% aluminium and 4% vanadium.<ref>{{cite book |last1=Zwicker |first1=Ulrich |title=Titan und Titanlegierungen |year=1974 |isbn=978-3-642-80588-2 |pages=4–29 |chapter=Herstellung des Metalls |doi=10.1007/978-3-642-80587-5_2}}</ref>

Several vanadium alloys show [[Superconductivity|superconducting]] behavior. The first [[A15 phase]] superconductor was a vanadium compound, V<sub>3</sub>Si, which was discovered in 1952.<ref>{{cite journal |last1=Hardy |first1=George F. |last2=Hulm |first2=John K. |date=15 February 1953 |title=Superconducting Silicides and Germanides |journal=Physical Review |volume=89 |issue=4 |pages=884 |bibcode=1953PhRv...89Q.884H |doi=10.1103/PhysRev.89.884}}</ref> [[Vanadium-gallium]] tape is used in [[superconductivity|superconducting]] magnets (17.5 [[tesla (unit)|teslas]] or 175,000 [[gauss (unit)|gauss]]). The structure of the superconducting A15 phase of V<sub>3</sub>Ga is similar to that of the more common [[niobium-tin|Nb<sub>3</sub>Sn]] and [[niobium-titanium|Nb<sub>3</sub>Ti]].<ref>{{cite journal |last1=Markiewicz |first1=W. |last2=Mains |first2=E. |last3=Vankeuren |first3=R. |last4=Wilcox |first4=R. |last5=Rosner |first5=C. |last6=Inoue |first6=H. |last7=Hayashi |first7=C. |last8=Tachikawa |first8=K. |date=January 1977 |title=A 17.5 Tesla superconducting concentric {{chem|Nb|3|Sn}} and {{chem|V|3|Ga}} magnet system |journal=IEEE Transactions on Magnetics |volume=13 |issue=1 |pages=35–37 |doi=10.1109/TMAG.1977.1059431}}</ref>

It has been found that a small amount, 40 to 270&nbsp;ppm, of vanadium in [[Wootz steel]] significantly improved the strength of the product, and gave it the distinctive patterning. The source of the vanadium in the original Wootz steel ingots remains unknown.<ref>{{cite journal |last1=Verhoeven |first1=J. D. |last2=Pendray |first2=A. H. |last3=Dauksch |first3=W. E. |date=September 1998 |title=The key role of impurities in ancient damascus steel blades |journal=JOM |volume=50 |issue=9 |pages=58–64 |bibcode=1998JOM....50i..58V |doi=10.1007/s11837-998-0419-y |s2cid=135854276}}</ref>

Vanadium can be used as a substitute for molybdenum in armor steel, though the alloy produced is far more brittle and prone to [[spalling]] on non-penetrating impacts.<ref>{{cite journal |last=Rohrmann |first=B. |year=1985 |title=Vanadium in South Africa (Metal Review Series no. 2) |journal=Journal of the Southern African Institute of Mining and Metallurgy |volume=85 |issue=5 |pages=141–150 |hdl=10520/AJA0038223X_1959}}</ref> The Third Reich was one of the most prominent users of such alloys, in armored vehicles like [[Tiger II]] or [[Jagdtiger]].<ref>{{cite journal |last=Overy |first=R. J. |year=1973 |title=Transportation and Rearmament in the Third Reich |journal=The Historical Journal |volume=16 |issue=2 |pages=389–409 |doi=10.1017/s0018246x00005926 |s2cid=153437214}}</ref>

=== Catalysts ===
[[File:Vanadium pentoxide powder.jpg|thumb|upright|[[Vanadium(V) oxide]] is a catalyst in the [[contact process]] for producing sulfuric acid.]]

Vanadium compounds are used extensively as catalysts;<ref>{{cite journal |last1=Langeslay |first1=Ryan R. |last2=Kaphan |first2=David M. |last3=Marshall |first3=Christopher L. |last4=Stair |first4=Peter C. |last5=Sattelberger |first5=Alfred P. |last6=Delferro |first6=Massimiliano |date=8 October 2018 |title=Catalytic Applications of Vanadium: A Mechanistic Perspective |journal=Chemical Reviews |volume=119 |issue=4 |pages=2128–2191 |doi=10.1021/acs.chemrev.8b00245 |osti=1509906 |pmid=30296048 |s2cid=52943647}}</ref> [[vanadium(V) oxide|Vanadium pentoxide]] V<sub>2</sub>O<sub>5</sub>, is used as a [[catalyst]] in manufacturing sulfuric acid by the [[contact process]]<ref>{{cite journal |last1=Eriksen |first1=K.M. |last2=Karydis |first2=D.A. |last3=Boghosian |first3=S. |last4=Fehrmann |first4=R. |date=August 1995 |title=Deactivation and Compound Formation in Sulfuric-Acid Catalysts and Model Systems |journal=Journal of Catalysis |volume=155 |issue=1 |pages=32–42 |doi=10.1006/jcat.1995.1185}}</ref> In this process [[sulfur dioxide]] ({{chem|SO|2}}) is oxidized to the [[sulfur trioxide|trioxide]] ({{chem|SO|3}}):<ref name="HollemanAF" /> In this [[redox reaction]], sulfur is oxidized from +4 to +6, and vanadium is reduced from +5 to +4:
:V<sub>2</sub>O<sub>5</sub> + SO<sub>2</sub> → 2 VO<sub>2</sub> + SO<sub>3</sub>

The catalyst is regenerated by oxidation with air:
:4 VO<sub>2</sub> + O<sub>2</sub> → 2 V<sub>2</sub>O<sub>5</sub>
Similar oxidations are used in the production of [[maleic anhydride]]:
:C<sub>4</sub>H<sub>10</sub>  + 3.5 O<sub>2</sub>  →   C<sub>4</sub>H<sub>2</sub>O<sub>3</sub>  +  4 H<sub>2</sub>O
[[Phthalic anhydride]] and several other bulk organic compounds are produced similarly. These [[green chemistry]] processes convert inexpensive feedstocks to highly functionalized, versatile intermediates.<ref name="Ullmann">{{Ullmann|doi=10.1002/14356007.a27_367|title=Vanadium and Vanadium Compounds|year=2000|last1=Bauer|first1=Günter|last2=Güther|first2=Volker|last3=Hess|first3=Hans|last4=Otto|first4=Andreas|last5=Roidl|first5=Oskar|last6=Roller|first6=Heinz|last7=Sattelberger|first7=Siegfried|isbn=3-527-30673-0}}</ref><ref>{{cite journal |last1=Abon |first1=Michel |last2=Volta |first2=Jean-Claude |date=September 1997 |title=Vanadium phosphorus oxides for n-butane oxidation to maleic anhydride |journal=Applied Catalysis A: General |volume=157 |issue=1–2 |pages=173–193 |doi=10.1016/S0926-860X(97)00016-1|bibcode=1997AppCA.157..173A }}</ref>

Vanadium is an important component of mixed metal oxide catalysts used in the oxidation of propane and propylene to [[acrolein]], acrylic acid or the ammoxidation of propylene to [[acrylonitrile]].<ref>{{cite book |title=Metal Oxides, Chemistry and Applications |date=2006 |publisher=CRC Press |isbn=978-0-8247-2371-2 |editor1-last=Fierro |editor1-first=J. G. L. |pages=415–455}}</ref>

=== Other uses ===
The [[vanadium redox battery]], a type of [[flow battery]], is an electrochemical cell consisting of aqueous vanadium ions in different oxidation states.<ref>{{cite journal |last1=Joerissen |first1=Ludwig |last2=Garche |first2=Juergen |last3=Fabjan |first3=Ch. |last4=Tomazic |first4=G. |date=March 2004 |title=Possible use of vanadium redox-flow batteries for energy storage in small grids and stand-alone photovoltaic systems |journal=Journal of Power Sources |volume=127 |issue=1–2 |pages=98–104 |bibcode=2004JPS...127...98J |doi=10.1016/j.jpowsour.2003.09.066}}</ref><ref name="RychcikSkyllas-Kazacos1988">{{cite journal |last1=Rychcik |first1=M. |last2=Skyllas-Kazacos |first2=M. |date=January 1988 |title=Characteristics of a new all-vanadium redox flow battery |journal=Journal of Power Sources |volume=22 |issue=1 |pages=59–67 |bibcode=1988JPS....22...59R |doi=10.1016/0378-7753(88)80005-3}}</ref> Batteries of this type were first proposed in the 1930s and developed commercially from the 1980s onwards. Cells use +5 and +2 formal oxidization state ions. Vanadium redox batteries are used commercially for [[grid energy storage]].<ref>{{Cite journal |last1=Li |first1=Liyu |last2=Kim |first2=Soowhan |last3=Wang |first3=Wei |last4=Vijayakumar |first4=M. |last5=Nie |first5=Zimin |last6=Chen |first6=Baowei |last7=Zhang |first7=Jianlu |last8=Xia |first8=Guanguang |last9=Hu |first9=Jianzhi |last10=Graff |first10=Gordon |last11=Liu |first11=Jun |last12=Yang |first12=Zhenguo |date=May 2011 |title=A Stable Vanadium Redox-Flow Battery with High Energy Density for Large-Scale Energy Storage |journal=Advanced Energy Materials |volume=1 |issue=3 |pages=394–400 |doi=10.1002/aenm.201100008 |bibcode=2011AdEnM...1..394L |s2cid=33277301}}</ref>

[[Vanadate]] can be used for protecting steel against rust and corrosion by [[conversion coating]].<ref>{{cite journal |last1=Guan |first1=H. |last2=Buchheit |first2=R. G. |date=1 March 2004 |title=Corrosion Protection of Aluminum Alloy 2024-T3 by Vanadate Conversion Coatings |journal=Corrosion |volume=60 |issue=3 |pages=284–296 |doi=10.5006/1.3287733}}</ref> Vanadium foil is used in [[cladding (metalworking)|cladding]] titanium to steel because it is compatible with both iron and titanium.<ref>{{cite journal |last1=Lositskii |first1=N. T. |last2=Grigor'ev |first2=A. A. |last3=Khitrova |first3=G. V. |date=December 1966 |title=Welding of chemical equipment made from two-layer sheet with titanium protective layer (review of foreign literature) |journal=Chemical and Petroleum Engineering |volume=2 |issue=12 |pages=854–856 |doi=10.1007/BF01146317 |bibcode=1966CPE.....2..854L |s2cid=108903737}}</ref> The moderate [[neutron capture|thermal neutron-capture cross-section]] and the short half-life of the isotopes produced by neutron capture makes vanadium a suitable material for the inner structure of a [[fusion reactor]].<ref>{{cite journal |last1=Matsui |first1=H. |last2=Fukumoto |first2=K. |last3=Smith |first3=D.L. |last4=Chung |first4=Hee M. |last5=van Witzenburg |first5=W. |last6=Votinov |first6=S.N. |date=October 1996 |title=Status of vanadium alloys for fusion reactors |url=https://zenodo.org/record/1259631 |url-status=live |journal=Journal of Nuclear Materials |volume=233-237 |pages=92–99 |bibcode=1996JNuM..233...92M |doi=10.1016/S0022-3115(96)00331-5 |archive-url=https://web.archive.org/web/20210215013608/https://zenodo.org/record/1259631 |archive-date=15 February 2021 |access-date=10 August 2018}}</ref><ref>{{cite web |title=Vanadium Data Sheet |url=http://www.wahchang.com/pages/products/data/pdf/Vanadium.pdf |archive-url=https://web.archive.org/web/20090225153938/http://www.wahchang.com/pages/products/data/pdf/Vanadium.pdf |archive-date=25 February 2009 |access-date=16 January 2009 |publisher=[[ATI Wah Chang]]}}</ref>

Vanadium can be added in small quantities <&nbsp;5% to [[Lithium iron phosphate battery|LFP battery]] cathodes to increase ionic conductivity.<ref>{{Cite patent|number=US7842420B2|title=Electrode material with enhanced ionic transport properties|gdate=2010-11-30|invent1=Wixom|invent2=Xu|inventor1-first=Michael R.|inventor2-first=Chuanjing|url=https://patents.google.com/patent/US7842420B2/en?oq=7842420}}</ref>

==== Proposed ====
[[Lithium vanadium oxide]] has been proposed for use as a high-energy-density anode for [[Lithium-ion battery|lithium-ion batteries]], at 745&nbsp;Wh/L when paired with a [[lithium cobalt oxide]] cathode.<ref>{{cite web |last=Kariatsumari |first=Koji |date=February 2008 |title=Li-Ion Rechargeable Batteries Made Safer |url=http://techon.nikkeibp.co.jp/article/HONSHI/20080129/146549/ |url-status=dead |archive-url=https://web.archive.org/web/20110912020554/http://techon.nikkeibp.co.jp/article/HONSHI/20080129/146549/ |archive-date=12 September 2011 |access-date=10 December 2008 |publisher=Nikkei Business Publications, Inc.}}</ref> [[Vanadium phosphate]]s have been proposed as the cathode in the [[lithium vanadium phosphate battery]], another type of lithium-ion battery.<ref>{{citation |last1=Saıdi |first1=M.Y. |title=Performance characteristics of lithium vanadium phosphate as a cathode material for lithium-ion batteries |date=1 June 2003 |journal=Journal of Power Sources |volume=119–121 |pages=266–272 |bibcode=2003JPS...119..266S |doi=10.1016/S0378-7753(03)00245-3 |last2=Barker |first2=J. |last3=Huang |first3=H. |last4=Swoyer |first4=J.L. |last5=Adamson |first5=G.}} Selected papers presented at the 11th International Meeting on Lithium Batteries</ref>

== Biological role ==
Vanadium has a more significant role in marine environments than terrestrial ones.<ref>{{cite book |title=Vanadium and Its Role in Life |publisher=CRC |year=1995 |isbn=978-0-8247-9383-8 |editor1-last=Sigel |editor1-first=Astrid |series=Metal Ions in Biological Systems |volume=31 |editor2-last=Sigel |editor2-first=Helmut}}</ref>
[[File:Bluebell tunicates Nick Hobgood.jpg|thumb|[[Tunicate]]s such as this bluebell tunicate contain vanadium as [[vanabins]].]]
[[File:Amanita muscaria 3 vliegenzwammen op rij.jpg|thumb|''[[Amanita muscaria]]'' contains [[amavadin]].]]

=== Vanadoenzymes ===
Several species of marine [[algae]] produce [[vanadium bromoperoxidase]] as well as the closely related [[chloroperoxidase]] (which may use a [[heme]] or vanadium cofactor) and [[iodoperoxidase]]s. The bromoperoxidase produces an estimated 1–2 million tons of [[bromoform]] and 56,000 tons of [[bromomethane]] annually.<ref>{{cite journal |last1=Gribble |first1=Gordon W. |date=1999 |title=The diversity of naturally occurring organobromine compounds |journal=Chemical Society Reviews |volume=28 |issue=5 |pages=335–346 |doi=10.1039/a900201d}}</ref> Most naturally occurring [[organobromine compound]]s are produced by this enzyme,<ref>{{cite journal |last1=Butler |first1=Alison |last2=Carter-Franklin |first2=Jayme N. |date=2004 |title=The role of vanadium bromoperoxidase in the biosynthesis of halogenated marine natural products |journal=Natural Product Reports |volume=21 |issue=1 |pages=180–188 |doi=10.1039/b302337k |pmid=15039842}}</ref> catalyzing the following reaction (R-H is hydrocarbon substrate):

{{block indent|R-H + Br<sup>−</sup> + H<sub>2</sub>O<sub>2</sub> → R-Br + H<sub>2</sub>O + OH<sup>−</sup>}}

A [[vanadium nitrogenase]] is used by some [[nitrogen fixation|nitrogen-fixing]] micro-organisms, such as ''[[Azotobacter]]''. In this role, vanadium serves in place of the more common [[molybdenum]] or [[iron]], and gives the [[nitrogenase]] slightly different properties.<ref>{{cite journal |last1=Robson |first1=R. L. |last2=Eady |first2=R. R. |last3=Richardson |first3=T. H. |last4=Miller |first4=R. W. |last5=Hawkins |first5=M. |last6=Postgate |first6=J. R. |date=1986 |title=The alternative nitrogenase of Azotobacter chroococcum is a vanadium enzyme |journal=Nature |volume=322 |issue=6077 |pages=388–390 |bibcode=1986Natur.322..388R |doi=10.1038/322388a0 |s2cid=4368841}}</ref>

=== Vanadium accumulation in tunicates ===
Vanadium is essential to [[tunicate]]s, where it is stored in the highly acidified [[vacuole]]s of certain blood cell types, designated [[vanadocyte]]s. [[Vanabins]] (vanadium-binding proteins) have been identified in the cytoplasm of such cells. The concentration of vanadium in the blood of [[Ascidiacea|ascidian]] tunicates is as much as ten million times higher{{specify|date=April 2014}}<ref>{{cite journal |last1=Smith |first1=M. J. |date=1989 |title=Vanadium biochemistry: The unknown role of vanadium-containing cells in ascidians (sea squirts) |journal=Experientia |volume=45 |issue=5 |pages=452–7 |doi=10.1007/BF01952027 |pmid=2656286 |s2cid=43534732}}</ref><ref>{{cite journal |last1=MacAra |first1=Ian G. |last2=McLeod |first2=G. C. |last3=Kustin |first3=Kenneth |date=1979 |title=Tunichromes and metal ion accumulation in tunicate blood cells |journal=Comparative Biochemistry and Physiology B |volume=63 |issue=3 |pages=299–302 |doi=10.1016/0305-0491(79)90252-9}}</ref> than the surrounding seawater, which normally contains 1 to 2&nbsp;μg/L.<ref>{{cite journal |last1=Trefry |first1=John H. |last2=Metz |first2=Simone |date=1989 |title=Role of hydrothermal precipitates in the geochemical cycling of vanadium |journal=Nature |volume=342 |issue=6249 |pages=531–533 |bibcode=1989Natur.342..531T |doi=10.1038/342531a0 |s2cid=4351410}}</ref><ref>{{cite journal |last1=Weiss |first1=H. |last2=Guttman |first2=M. A. |last3=Korkisch |first3=J. |last4=Steffan |first4=I. |date=1977 |title=Comparison of methods for the determination of vanadium in sea-water |journal=Talanta |volume=24 |issue=8 |pages=509–11 |doi=10.1016/0039-9140(77)80035-0 |pmid=18962130}}</ref> The function of this vanadium concentration system and these vanadium-bearing proteins is still unknown, but the vanadocytes are later deposited just under the outer surface of the tunic, where they may deter [[predation]].<ref>{{cite book |last1=Ruppert |first1=Edward E. |title=Invertebrate Zoology |last2=Fox |first2=Richard, S. |last3=Barnes |first3=Robert D. |date=2004 |publisher=Cengage Learning |isbn=978-81-315-0104-7 |edition=7th |pages=947}}</ref>

=== Fungi ===
''[[Amanita muscaria]]'' and related species of macrofungi accumulate vanadium (up to 500&nbsp;mg/kg in dry weight). Vanadium is present in the [[coordination complex]] [[amavadin]]<ref>{{cite journal |last1=Kneifel |first1=Helmut |last2=Bayer |first2=Ernst |date=June 1973 |title=Determination of the Structure of the Vanadium Compound, Amavadine, from Fly Agaric |journal=Angewandte Chemie International Edition in English |volume=12 |issue=6 |pages=508 |doi=10.1002/anie.197305081}}</ref> in fungal fruit-bodies. The biological importance of the accumulation is unknown.<ref>{{cite journal |last1=Falandysz |first1=J. |last2=Kunito |first2=T. |last3=Kubota |first3=R. |last4=Lipka |first4=K. |last5=Mazur |first5=A. |last6=Falandysz |first6=Justyna J. |last7=Tanabe |first7=S. |date=31 August 2007 |title=Selected elements in fly agaric Amanita muscaria |journal=Journal of Environmental Science and Health, Part A |volume=42 |issue=11 |pages=1615–1623 |doi=10.1080/10934520701517853 |pmid=17849303 |bibcode=2007JESHA..42.1615F |s2cid=26185534}}</ref><ref>{{cite journal |last1=Berry |first1=Robert E. |last2=Armstrong |first2=Elaine M. |last3=Beddoes |first3=Roy L. |last4=Collison |first4=David |last5=Ertok |first5=S. Nigar |last6=Helliwell |first6=Madeleine |last7=Garner |first7=C. David |date=15 March 1999 |title=The Structural Characterization of Amavadin |journal=Angewandte Chemie |volume=38 |issue=6 |pages=795–797 |doi=10.1002/(SICI)1521-3773(19990315)38:6<795::AID-ANIE795>3.0.CO;2-7 |pmid=29711812|doi-access=free }}</ref> Toxic or [[peroxidase]] enzyme functions have been suggested.<ref name="da Silva Fraústo 2013">{{cite journal |last1=da Silva |first1=José A.L. |last2=Fraústo da Silva |first2=João J.R. |last3=Pombeiro |first3=Armando J.L. |date=August 2013 |title=Amavadin, a vanadium natural complex: Its role and applications |journal=Coordination Chemistry Reviews |volume=257 |issue=15–16 |pages=2388–2400 |doi=10.1016/j.ccr.2013.03.010}}</ref>

=== Mammals ===
Deficiencies in vanadium result in reduced growth in rats.<ref>{{cite journal |last1=Schwarz |first1=Klaus |last2=Milne |first2=David B. |date=22 October 1971 |title=Growth Effects of Vanadium in the Rat |journal=Science |volume=174 |issue=4007 |pages=426–428 |bibcode=1971Sci...174..426S |doi=10.1126/science.174.4007.426 |pmid=5112000 |s2cid=24362265}}</ref> The U.S. Institute of Medicine has not confirmed that vanadium is an essential nutrient for humans, so neither a Recommended Dietary Intake nor an Adequate Intake have been established. Dietary intake is estimated at 6 to 18&nbsp;μg/day, with less than 5% absorbed. The [[tolerable upper intake level|Tolerable Upper Intake Level]] (UL) of dietary vanadium, beyond which adverse effects may occur, is set at 1.8&nbsp;mg/day.<ref>Nickel. IN: [https://www.nap.edu/read/10026/chapter/15 Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Copper] {{Webarchive|url=https://web.archive.org/web/20170922174144/https://www.nap.edu/read/10026/chapter/15|date=22 September 2017}}. National Academy Press. 2001, PP. 532–543.</ref>

=== Research ===
[[Vanadyl sulfate]] as a dietary supplement has been researched as a means of increasing insulin sensitivity or otherwise improving glycemic control in people who are diabetic. Some of the trials had significant treatment effects but were deemed as being of poor study quality. The amounts of vanadium used in these trials (30 to 150&nbsp;mg) far exceeded the safe upper limit.<ref name="Smith2008">{{cite journal |last1=Smith |first1=D.M. |last2=Pickering |first2=R.M. |last3=Lewith |first3=G.T. |date=31 January 2008 |title=A systematic review of vanadium oral supplements for glycaemic control in type 2 diabetes mellitus |journal=QJM |volume=101 |issue=5 |pages=351–358 |doi=10.1093/qjmed/hcn003 |pmid=18319296}}</ref><ref>{{cite journal |year=2009 |title=Vanadium (vanadyl sulfate). Monograph |journal=Altern Med Rev |volume=14 |issue=2 |pages=177–80 |pmid=19594227}}</ref> The conclusion of the systemic review was "There is no rigorous evidence that oral vanadium supplementation improves glycaemic control in type 2 diabetes. The routine use of vanadium for this purpose cannot be recommended."<ref name="Smith2008" />

In [[astrobiology]], it has been suggested that discrete vanadium accumulations on [[Mars]] could be a potential microbial [[biosignature]] when used in conjunction with [[Raman spectroscopy]] and morphology.<ref name="Biosignature Vanadium">{{cite news |last=Lynch |first=Brendan M. |date=21 September 2017 |title=Hope to discover sure signs of life on Mars? New research says look for the element vanadium |work=PhysOrg |url=https://phys.org/news/2017-09-life-mars-element-vanadium.html |url-status=live |access-date=2017-10-14 |archive-url=https://web.archive.org/web/20211011173212/https://phys.org/news/2017-09-life-mars-element-vanadium.html |archive-date=11 October 2021}}</ref><ref name="Vanadium Craig">{{cite journal |last1=Marshall |first1=C. P |last2=Olcott Marshall |first2=A |last3=Aitken |first3=J. B |last4=Lai |first4=B |last5=Vogt |first5=S |last6=Breuer |first6=P |last7=Steemans |first7=P |last8=Lay |first8=P. A |year=2017 |title=Imaging of Vanadium in Microfossils: A New Potential Biosignature |journal=Astrobiology |volume=17 |issue=11 |pages=1069–1076 |bibcode=2017AsBio..17.1069M |doi=10.1089/ast.2017.1709 |osti=1436103 |pmid=28910135}}</ref>

== Safety ==
All vanadium compounds should be considered toxic.<ref>{{cite journal |last=Srivastava |first=A. K. |year=2000 |title=Anti-diabetic and toxic effects of vanadium compounds |journal=Molecular and Cellular Biochemistry |volume=206 |issue=206 |pages=177–182 |doi=10.1023/A:1007075204494 |pmid=10839208 |s2cid=8871862}}</ref> Tetravalent [[vanadyl sulfate|VOSO<sub>4</sub>]] has been reported to be at least 5 times more toxic than trivalent V<sub>2</sub>O<sub>3</sub>.<ref>{{cite journal |last=Roschin |first=A. V. |date=1967 |title=Toksikologiia soedineniĭ vanadiia, primeneniaemykh<!--sic: should probably be primeniaemykh--> v sovremennoĭ promyshlennosti |trans-title=Toxicology of vanadium compounds used in modern industry |journal=Gigiena i Sanitariia (Water Res.) |language=ru |volume=32 |issue=6 |pages=26–32 |pmid=5605589}}<!--Russian title given only in Latin script. Cyrillic presumably would be: Токсикология соединений ванадия, применяемых в современной промышленности, and journal Гигиена и санитария --></ref> The US [[Occupational Safety and Health Administration]] (OSHA) has set an exposure limit of 0.05&nbsp;mg/m<sup>3</sup> for vanadium pentoxide dust and 0.1&nbsp;mg/m<sup>3</sup> for vanadium pentoxide fumes in workplace air for an 8-hour workday, 40-hour work week.<ref name="OSHA">{{cite web |title=Occupational Safety and Health Guidelines for Vanadium Pentoxide |url=http://www.osha.gov/SLTC/healthguidelines/vanadiumpentoxidedust/recognition.html |url-status=dead |archive-url=https://web.archive.org/web/20090106063227/http://www.osha.gov/SLTC/healthguidelines/vanadiumpentoxidedust/recognition.html |archive-date=6 January 2009 |access-date=29 January 2009 |publisher=Occupational Safety and Health Administration}}</ref> The US [[National Institute for Occupational Safety and Health]] (NIOSH) has recommended that 35&nbsp;mg/m<sup>3</sup> of vanadium be considered immediately dangerous to life and health, that is, likely to cause permanent health problems or death.<ref name="OSHA" />

Vanadium compounds are poorly absorbed through the gastrointestinal system. Inhalation of vanadium and vanadium compounds results primarily in adverse effects on the respiratory system.<ref>{{cite book |last=Sax |first=N. I. |title=Dangerous Properties of Industrial Materials |date=1984 |publisher=Van Nostrand Reinhold |edition=6th |pages=2717–2720}}</ref><ref name="ress">{{cite journal |last1=Ress |first1=N. B. |last2=Chou |first2=B. J. |last3=Renne |first3=R. A. |last4=Dill |first4=J. A. |last5=Miller |first5=R. A. |last6=Roycroft |first6=J. H. |last7=Hailey |first7=J. R. |last8=Haseman |first8=J. K. |last9=Bucher |first9=J. R. |date=1 August 2003 |title=Carcinogenicity of Inhaled Vanadium Pentoxide in F344/N Rats and B6C3F1 Mice |journal=Toxicological Sciences |volume=74 |issue=2 |pages=287–296 |doi=10.1093/toxsci/kfg136 |pmid=12773761|doi-access=free }}</ref><ref>{{cite journal |last1=Wörle-Knirsch |first1=Jörg M. |last2=Kern |first2=Katrin |last3=Schleh |first3=Carsten |last4=Adelhelm |first4=Christel |last5=Feldmann |first5=Claus |last6=Krug |first6=Harald F. |name-list-style=amp |date=2007 |title=Nanoparticulate Vanadium Oxide Potentiated Vanadium Toxicity in Human Lung Cells |journal=Environmental Science and Technology |volume=41 |issue=1 |pages=331–336 |bibcode=2007EnST...41..331W |doi=10.1021/es061140x |pmid=17265967}}</ref> Quantitative data are, however, insufficient to derive a subchronic or chronic inhalation reference dose. Other effects have been reported after oral or inhalation exposures on blood parameters,<ref>{{cite journal |last1=Ścibior |first1=A. |last2=Zaporowska |first2=H. |last3=Ostrowski |first3=J. |date=2006 |title=Selected haematological and biochemical parameters of blood in rats after subchronic administration of vanadium and/or magnesium in drinking water |journal=Archives of Environmental Contamination and Toxicology |volume=51 |issue=2 |pages=287–295 |doi=10.1007/s00244-005-0126-4 |pmid=16783625 |bibcode=2006ArECT..51..287S |s2cid=43805930}}</ref><ref>{{cite journal |last1=González-Villalva |first1=Adriana |last2=Fortoul |first2=Teresa I |last3=Avila-Costa |first3=Maria Rosa |last4=Piñón-Zarate |first4=Gabriela |last5=Rodriguez-Lara |first5=Vianey |last6=Martínez-Levy |first6=Gabriela |last7=Rojas-Lemus |first7=Marcela |last8=Bizarro-Nevarez |first8=Patricia |last9=Díaz-Bech |first9=Patricia |last10=Mussali-Galante |first10=Patricia |last11=Colin-Barenque |first11=Laura |date=April 2006 |title=Thrombocytosis induced in mice after subacute and subchronic V2O5 inhalation |journal=Toxicology and Industrial Health |volume=22 |issue=3 |pages=113–116 |doi=10.1191/0748233706th250oa |pmid=16716040 |bibcode=2006ToxIH..22..113G |s2cid=9986509}}</ref> liver,<ref>{{cite journal |last1=Kobayashi |first1=Kazuo |last2=Himeno |first2=Seiichiro |last3=Satoh |first3=Masahiko |last4=Kuroda |first4=Junji |last5=Shibata |first5=Nobuo |last6=Seko |first6=Yoshiyuki |last7=Hasegawa |first7=Tatsuya |date=2006 |title=Pentavalent vanadium induces hepatic metallothionein through interleukin-6-dependent and -independent mechanisms |journal=Toxicology |volume=228 |issue=2–3 |pages=162–170 |doi=10.1016/j.tox.2006.08.022 |pmid=16987576|bibcode=2006Toxgy.228..162K }}</ref> neurological development,<ref>{{cite journal |last1=Soazo |first1=Marina |last2=Garcia |first2=Graciela Beatriz |date=2007 |title=Vanadium exposure through lactation produces behavioral alterations and CNS myelin deficit in neonatal rats |journal=Neurotoxicology and Teratology |volume=29 |issue=4 |pages=503–510 |doi=10.1016/j.ntt.2007.03.001 |pmid=17493788|bibcode=2007NTxT...29..503S }}</ref> and other organs<ref>{{cite journal |last1=Barceloux |first1=Donald G. |year=1999 |title=Vanadium |journal=Clinical Toxicology |volume=37 |issue=2 |pages=265–278 |doi=10.1081/CLT-100102425 |pmid=10382561}}</ref> in rats.

There is little evidence that vanadium or vanadium compounds are reproductive toxins or [[teratogen]]s. Vanadium pentoxide was reported to be carcinogenic in male rats and in male and female mice by inhalation in an NTP study,<ref name="ress" /> although the interpretation of the results has been disputed a few years after the report.<ref>{{cite journal |last=Duffus |first=J. H. |date=2007 |title=Carcinogenicity classification of vanadium pentoxide and inorganic vanadium compounds, the NTP study of carcinogenicity of inhaled vanadium pentoxide, and vanadium chemistry |journal=[[Regulatory Toxicology and Pharmacology]] |volume=47 |issue=1 |pages=110–114 |doi=10.1016/j.yrtph.2006.08.006 |pmid=17030368}}</ref> The carcinogenicity of vanadium has not been determined by the [[United States Environmental Protection Agency]].<ref>{{cite web |last=Opreskos |first=Dennis M. |date=1991 |title=Toxicity Summary for Vanadium |url=https://rais.ornl.gov/tox/profiles/vanadium_f_V1.html |url-status=live |archive-url=https://web.archive.org/web/20211006060858/https://rais.ornl.gov/tox/profiles/vanadium_f_V1.html |archive-date=6 October 2021 |access-date=8 November 2008 |publisher=Oak Ridge National Laboratory}}</ref>

Vanadium traces in [[diesel fuel]]s are the main fuel component in [[high temperature corrosion]]. During combustion, vanadium oxidizes and reacts with sodium and sulfur, yielding [[vanadate]] compounds with melting points as low as {{Cvt|530|C}}, which attack the [[passivation (chemistry)|passivation layer]] on steel and render it susceptible to corrosion. The solid vanadium compounds also abrade engine components.<ref>{{cite book |last1=Woodyard |first1=Doug |url=https://books.google.com/books?id=RC_k4q6y-JIC&pg=PA92 |title=Pounder's Marine Diesel Engines and Gas Turbines |date=2009-08-18 |isbn=978-0-08-094361-9 |page=92|publisher=Butterworth-Heinemann }}</ref><ref>{{cite book |last1=Totten |first1=George E. |url=https://books.google.com/books?id=J_AkNu-Y1wQC&pg=PA152 |title=Fuels and Lubricants Handbook: Technology, Properties, Performance, and Testing |last2=Westbrook |first2=Steven R. |last3=Shah |first3=Rajesh J. |date=2003-06-01 |isbn=978-0-8031-2096-9 |page=152}}</ref>

== See also ==
*{{annotated link|Flow battery}}
*{{annotated link|Green Giant mine}}
*{{annotated link|Grid energy storage}}
*{{annotated link|Vanadium carbide}}
*{{annotated link|Vanadium redox battery}}
*{{annotated link|Vanadium tetrachloride}}
*{{annotated link|Vanadium(V) oxide}}
*{{annotated link|International Vanadium Symposium}}
*{{annotated link|Vanadium cycle}}

== References ==
{{Reflist}}

== Further reading ==
*{{cite book|chapter=Modeling the Biological Chemistry of Vanadium: Structural and Reactivity Studies Elucidating Biological Function|editor=Hill, Hugh A.O.|display-editors=etal|title=Metal sites in proteins and models: phosphatases, Lewis acids, and vanadium|publisher=Springer|date=1999|isbn=978-3-540-65553-4|chapter-url=https://books.google.com/books?id=ZF5aNOeHd5sC&pg=PA51|author=Slebodnick, Carla|display-authors=etal}}

== External links ==
{{Commons|Vanadium}}
{{Wiktionary|vanadium}}
* {{cite EB9 |wstitle = Vanadium |volume= XXIV | page=54 |short=1 }}
*[http://www.periodicvideos.com/videos/023.htm Vanadium] at ''[[The Periodic Table of Videos]]'' (University of Nottingham)

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{{Vanadium compounds}}

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[[Category:Vanadium| ]]
[[Category:Chemical elements]]
[[Category:Transition metals]]
[[Category:Dietary minerals]]
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[[Category:Chemical elements with body-centered cubic structure]]
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