Vanadium#Applications

Vanadium was 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.{{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}}

In 1831 Swedish chemist Nils Gabriel Sefström rediscovered the element in a new oxide he found while working with iron ores. 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.{{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}} Sefström chose a name beginning with V, which had not yet been assigned to any element. He called the element vanadium after Old Norse Vanadís (another name for the Norse Vanir goddess Freyja, whose attributes include beauty and fertility), because of the many beautifully colored chemical compounds it produces. 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.{{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=}} In 1831, the geologist George William Featherstonhaugh suggested that vanadium should be renamed "rionium" after del Río, but this suggestion was not followed.{{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}}

File:1910Ford-T.jpg used vanadium steel in its chassis.]]

As vanadium is usually found combined with other elements, the isolation of vanadium metal was difficult.{{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}} In 1831, 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, VCl₂, with hydrogen.{{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}} In 1927, pure vanadium was produced by reducing vanadium pentoxide with calcium.{{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}}

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}}).{{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}} 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.{{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}}{{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}}

In 1911, German chemist Martin Henze discovered vanadium in the hemovanadin proteins found in blood cells (or coelomic cells) of Ascidiacea (sea squirts).{{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}}{{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}}

File:Vanadium-bar.jpg and macro-etched]]

Vanadium is an average-hard, ductile, steel-blue metal. Vanadium is usually described as "soft", because it is ductile, malleable, and not brittle.{{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}}{{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}} Vanadium is harder than most metals and steels (see Hardnesses of the elements (data page) and iron). It has good resistance to corrosion and it is stable against alkalis and sulfuric and hydrochloric acids.{{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}} It is oxidized in air at about 933 K (660 °C, 1220 °F), although an oxide passivation layer forms even at room temperature.{{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 |url=https://xlink.rsc.org/?DOI=C9CP04045E |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 }} It also reacts with hydrogen peroxide.

{{Main|Isotopes of vanadium}}

Naturally occurring vanadium is composed of one stable isotope, ⁵¹V, and one radioactive isotope, ⁵⁰V. The latter has a half-life of 2.71×10¹⁷ years and a natural abundance of 0.25%. ⁵¹V has a nuclear spin of {{frac|7|2}}, which is useful for NMR spectroscopy.{{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}} Twenty-four artificial radioisotopes have been characterized, ranging in mass number from 40 to 65. The most stable of these isotopes are ⁴⁹V with a half-life of 330 days, and ⁴⁸V 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 metastable excited states.{{NUBASE 2003}} Electron capture is the main decay mode for isotopes lighter than ⁵¹V. 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.

{{Main|Vanadium compounds}}

File:Vanadiumoxidationstates.jpg

The chemistry of vanadium is noteworthy for the accessibility of the four adjacent oxidation states 2–5. In an aqueous solution, vanadium forms metal aquo complexes of which the colors are lilac [V(H₂O)₆]²⁺, green [V(H₂O)₆]³⁺, blue [VO(H₂O)₅]²⁺, yellow-orange oxides [VO(H₂O)₅]³⁺, 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 derivatives, which contain the VO²⁺ center.

Ammonium vanadate(V) (NH₄VO₃) 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 V(CO)₆, {{chem|[V(CO)|6|]|-}} and substituted derivatives.

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.

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 [VO₂(H₂O)₄]⁺ is replaced by the blue color of [VO(H₂O)₅]²⁺, followed by the green color of [V(H₂O)₆]³⁺ and then the violet color of [V(H₂O)₆]²⁺. Another potential vanadium battery based on VB₂ uses multiple oxidation state to allow for 11 electrons to be released per VB₂, giving it higher energy capacity by order of compared to Li-ion and gasoline per unit volume.{{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}} VB₂ 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.

File:decavanadate polyhedra.png structure]]

In an aqueous solution, vanadium(V) forms an extensive family of oxyanions as established by ⁵¹V NMR spectroscopy. The interrelationships in this family are described by the predominance diagram, which shows at least 11 species, depending on pH and concentration.{{Greenwood&Earnshaw|page=984}} 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. Orthovanadate V{{chem|O|4|3−}} is used in protein crystallography{{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 }} to study the biochemistry of phosphate.{{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}} Besides that, this anion also has been shown to interact with the activity of some specific enzymes.{{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}}{{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}} The tetrathiovanadate [VS₄]³⁻ is analogous to the orthovanadate ion.{{Greenwood&Earnshaw|page=988}}

At lower pH values, the monomer [HVO₄]²⁻ and dimer [V₂O₇]⁴⁻ are formed, with the monomer predominant at a vanadium concentration of less than c. 10⁻²M (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.{{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 }}{{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}} As the pH is reduced, further protonation and condensation to polyvanadates occur: at pH 4–6 [H₂VO₄]⁻ is predominant at pV greater than ca. 4, while at higher concentrations trimers and tetramers are formed.{{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}} Between pH 2–4 decavanadate predominates, its formation from orthovanadate is represented by this condensation reaction:

:10 [VO₄]³⁻ + 24 H⁺ → [V₁₀O₂₈]⁶⁻ + 12 H₂O

File:Vanadium crystal.jpg

In decavanadate, each V(V) center is surrounded by six oxide ligands. Vanadic acid, H₃VO₄, exists only at very low concentrations because protonation of the tetrahedral species [H₂VO₄]⁻ results in the preferential formation of the octahedral [VO₂(H₂O)₄]⁺ species.{{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}} In strongly acidic solutions, pH < 2, [VO₂(H₂O)₄]⁺ is the predominant species, while the oxide V₂O₅ precipitates from solution at high concentrations. The oxide is formally the acid anhydride of vanadic acid. The structures of many vanadate compounds have been determined by X-ray crystallography.

File:VinwaterPourbaixdiagram2.svg for vanadium in water, which shows the redox potentials between various vanadium species in different oxidation states{{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}}]]

Vanadium(V) forms various peroxo complexes, most notably in the active site of the vanadium-containing bromoperoxidase enzymes. The species VO(O₂)(H₂O)₄⁺ 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 M₃V(O₂)₄ nH₂O (M= Li, Na, etc.), in which the vanadium has an 8-coordinate dodecahedral structure.{{Greenwood&Earnshaw}}, p994.{{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}}

Twelve binary halides, compounds with the formula VX_n (n=2..5), are known.{{Greenwood&Earnshaw2nd|page=989}} VI₄, VCl₅, VBr₅, and VI₅ do not exist or are extremely unstable. In combination with other reagents, VCl₄ is used as a catalyst for the polymerization of dienes. Like all binary halides, those of vanadium are Lewis acidic, especially those of V(IV) and V(V). Many of the halides form octahedral complexes with the formula VX_nL_6−n (X= halide; L= other ligand).

Many vanadium oxyhalides (formula VO_mX_n) are known.{{Greenwood&Earnshaw|page=993}} The oxytrichloride and oxytrifluoride (VOCl₃ and VOF₃) are the most widely studied. Akin to POCl₃, they are volatile,{{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}} adopt tetrahedral structures in the gas phase, and are Lewis acidic.{{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}}

File:Vanadyl-acetylacetonate-from-xtal-3D-balls.png of VO(O₂C₅H₇)₂]]

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)₇]⁴⁻. 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 V⁴⁺ is dominated by the vanadyl center, VO²⁺, which binds four other ligands strongly and one weakly (the one trans to the vanadyl center). An example is vanadyl acetylacetonate (V(O)(O₂C₅H₇)₂). 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 VOCl₂(NMe₃)₂.{{Greenwood&Earnshaw2nd|page=995}} The coordination chemistry of V⁵⁺ is dominated by the relatively stable dioxovanadium coordination complexes{{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}} 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.{{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}}

{{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.{{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 }} Vanadium carbonyl, V(CO)₆, is a rare example of a paramagnetic metal carbonyl. Reduction yields V{{chem|(CO)|6|−}} (isoelectronic with Cr(CO)₆), which may be further reduced with sodium in liquid ammonia to yield V{{chem|(CO)|5|3−}} (isoelectronic with Fe(CO)₅).{{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 }}{{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}}

File:Vanadinite, goethite(2).jpg]]

Metallic vanadium is rare in nature (known as native vanadium),{{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}}{{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}} having been found among fumaroles of the Colima Volcano, but vanadium compounds occur naturally in about 65 different minerals.

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.{{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}} 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).{{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}}{{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}}{{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}} For several years this patrónite (VS₄){{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}} 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.{{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}} With the production of uranium in the 1910s and 1920s from carnotite ({{nowrap|K₂(UO₂)₂(VO₄)₂·3H₂O}}) vanadium became available as a side product of uranium production. Vanadinite ({{nowrap|Pb₅(VO₄)₃Cl}}) 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.{{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}}

Vanadium is mined mostly in China, South Africa and eastern Russia. In 2022 these three countries mined more than 96% of the 100,000 tons of produced vanadium, with China providing 70%.{{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}}

Fumaroles of Colima are known of being vanadium-rich, depositing other vanadium minerals, that include shcherbinaite (V₂O₅) and colimaite (K₃VS₄).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{{cite web|url=http://www.mindat.org/min-43604.html |title=Vanadium: Vaandium mineral information and data |website=Mindat.org |accessdate=2016-03-02}}{{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}}

Vanadium is also present in bauxite and deposits of crude oil, coal, oil shale, and tar sands. In crude oil, concentrations up to 1200 ppm have been reported. When such oil products are burned, traces of vanadium may cause corrosion in engines and boilers.{{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}} An estimated 110,000 tons of vanadium per year are released into the atmosphere by burning fossil fuels.{{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}} Black shales are also a potential source of vanadium. During WWII some vanadium was extracted from alum shales in the south of Sweden.{{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}}

In the universe, the cosmic abundance of vanadium is 0.0001%, making the element nearly as common as copper or zinc.{{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}} Vanadium is the 19th most abundant element in the crust.{{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}} It is detected spectroscopically in light from the Sun and sometimes in the light from other stars.{{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 }} The vanadyl ion is also abundant in seawater, having an average concentration of 30 nM (1.5 mg/m³). Some mineral water springs also contain the ion in high concentrations. For example, springs near Mount Fuji contain as much as 54 μg per liter.

File:Vanadium-production(en).svg

File:Vanadium crystal vakuum sublimed.jpg crystals (99.9%)]]

Vanadium metal is obtained by a multistep process that begins with roasting crushed ore with NaCl or Na₂CO₃ at about 850 °C to give sodium metavanadate (NaVO₃). 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.{{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}} 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:{{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}}

:2 V + 3 I₂ {{eqm}} 2 VI₃

File:FerroVanadium.jpg

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.

File:Knarre.jpg

Approximately 85% of the vanadium produced is used as ferrovanadium or as a steel additive. 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.{{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}} From that time on, vanadium steel was used for applications in axles, bicycle frames, crankshafts, 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 tool steels (HSS) have a vanadium content of 1–5%. For high-speed tool steels, a hardness above HRC 60 can be achieved. HSS steel is used in surgical instruments and tools.{{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}} 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.{{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}}

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 engines, high-speed airframes and dental implants. The most common alloy for seamless tubing is Titanium 3/2.5 containing 2.5% vanadium, the titanium alloy of choice in the aerospace, defense, and bicycle industries.{{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}} Another common alloy, primarily produced in sheets, is Titanium 6AL-4V, a titanium alloy with 6% aluminium and 4% vanadium.{{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}}

Several vanadium alloys show superconducting behavior. The first A15 phase superconductor was a vanadium compound, V₃Si, which was discovered in 1952.{{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}} Vanadium-gallium tape is used in superconducting magnets (17.5 teslas or 175,000 gauss). The structure of the superconducting A15 phase of V₃Ga is similar to that of the more common Nb₃Sn and Nb₃Ti.{{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}}

It has been found that a small amount, 40 to 270 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.{{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}}

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.{{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}} The Third Reich was one of the most prominent users of such alloys, in armored vehicles like Tiger II or Jagdtiger.{{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}}

File:Vanadium pentoxide powder.jpg is a catalyst in the contact process for producing sulfuric acid.]]

Vanadium compounds are used extensively as catalysts;{{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}} Vanadium pentoxide V₂O₅, is used as a catalyst in manufacturing sulfuric acid by the contact process{{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}} In this process sulfur dioxide ({{chem|SO|2}}) is oxidized to the trioxide ({{chem|SO|3}}): In this redox reaction, sulfur is oxidized from +4 to +6, and vanadium is reduced from +5 to +4:

:V₂O₅ + SO₂ → 2 VO₂ + SO₃

The catalyst is regenerated by oxidation with air:

:4 VO₂ + O₂ → 2 V₂O₅

Similar oxidations are used in the production of maleic anhydride:

:C₄H₁₀ + 3.5 O₂ → C₄H₂O₃ + 4 H₂O

Phthalic anhydride and several other bulk organic compounds are produced similarly. These green chemistry processes convert inexpensive feedstocks to highly functionalized, versatile intermediates.{{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}}{{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}}

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.{{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}}

The vanadium redox battery, a type of flow battery, is an electrochemical cell consisting of aqueous vanadium ions in different oxidation states.{{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}}{{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}} 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.{{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}}

Vanadate can be used for protecting steel against rust and corrosion by conversion coating.{{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}} Vanadium foil is used in cladding titanium to steel because it is compatible with both iron and titanium.{{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}} The moderate 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.{{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}}{{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}}

Vanadium can be added in small quantities < 5% to LFP battery cathodes to increase ionic conductivity.{{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}}

Lithium vanadium oxide has been proposed for use as a high-energy-density anode for lithium-ion batteries, at 745 Wh/L when paired with a lithium cobalt oxide cathode.{{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.}} Vanadium phosphates have been proposed as the cathode in the lithium vanadium phosphate battery, another type of lithium-ion battery.{{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

Vanadium has a more significant role in marine environments than terrestrial ones.{{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}}

File:Bluebell tunicates Nick Hobgood.jpgs such as this bluebell tunicate contain vanadium as vanabins.]]

File:Amanita muscaria 3 vliegenzwammen op rij.jpg contains amavadin.]]

Several species of marine algae produce vanadium bromoperoxidase as well as the closely related chloroperoxidase (which may use a heme or vanadium cofactor) and iodoperoxidases. The bromoperoxidase produces an estimated 1–2 million tons of bromoform and 56,000 tons of bromomethane annually.{{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}} Most naturally occurring organobromine compounds are produced by this enzyme,{{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}} catalyzing the following reaction (R-H is hydrocarbon substrate):

{{block indent|R-H + Br⁻ + H₂O₂ → R-Br + H₂O + OH⁻}}

A vanadium nitrogenase is used by some 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.{{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}}

Vanadium is essential to tunicates, where it is stored in the highly acidified vacuoles of certain blood cell types, designated vanadocytes. Vanabins (vanadium-binding proteins) have been identified in the cytoplasm of such cells. The concentration of vanadium in the blood of ascidian tunicates is as much as ten million times higher{{specify|date=April 2014}}{{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}}{{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}} than the surrounding seawater, which normally contains 1 to 2 μg/L.{{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}}{{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}} 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.{{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}}

Amanita muscaria and related species of macrofungi accumulate vanadium (up to 500 mg/kg in dry weight). Vanadium is present in the coordination complex amavadin{{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}} in fungal fruit-bodies. The biological importance of the accumulation is unknown.{{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}}{{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 }} Toxic or peroxidase enzyme functions have been suggested.{{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}}

Deficiencies in vanadium result in reduced growth in rats.{{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}} 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 μg/day, with less than 5% absorbed. The Tolerable Upper Intake Level (UL) of dietary vanadium, beyond which adverse effects may occur, is set at 1.8 mg/day.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.

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 mg) far exceeded the safe upper limit.{{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}}{{cite journal |year=2009 |title=Vanadium (vanadyl sulfate). Monograph |journal=Altern Med Rev |volume=14 |issue=2 |pages=177–80 |pmid=19594227}} 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."

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.{{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}}{{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}}

All vanadium compounds should be considered toxic.{{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}} Tetravalent VOSO₄ has been reported to be at least 5 times more toxic than trivalent V₂O₃.{{cite journal |last=Roschin |first=A. V. |date=1967 |title=Toksikologiia soedineniĭ vanadiia, primeneniaemykh 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}} The US Occupational Safety and Health Administration (OSHA) has set an exposure limit of 0.05 mg/m³ for vanadium pentoxide dust and 0.1 mg/m³ for vanadium pentoxide fumes in workplace air for an 8-hour workday, 40-hour work week.{{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}} The US National Institute for Occupational Safety and Health (NIOSH) has recommended that 35 mg/m³ of vanadium be considered immediately dangerous to life and health, that is, likely to cause permanent health problems or death.

Vanadium compounds are poorly absorbed through the gastrointestinal system. Inhalation of vanadium and vanadium compounds results primarily in adverse effects on the respiratory system.{{cite book |last=Sax |first=N. I. |title=Dangerous Properties of Industrial Materials |date=1984 |publisher=Van Nostrand Reinhold |edition=6th |pages=2717–2720}}{{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 }}{{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}} 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,{{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}}{{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}} liver,{{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 }} neurological development,{{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 }} and other organs{{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}} in rats.

There is little evidence that vanadium or vanadium compounds are reproductive toxins or teratogens. Vanadium pentoxide was reported to be carcinogenic in male rats and in male and female mice by inhalation in an NTP study, although the interpretation of the results has been disputed a few years after the report.{{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}} The carcinogenicity of vanadium has not been determined by the United States Environmental Protection Agency.{{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}}

Vanadium traces in diesel fuels 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 layer on steel and render it susceptible to corrosion. The solid vanadium compounds also abrade engine components.{{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 }}{{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}}

• {{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}}

{{Reflist}}

• {{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}}

{{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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