Vanadium
Encyclopedia
Vanadium is a chemical element
with the symbol V and atomic number
23. It is a hard, silvery gray, ductile and malleable transition metal
. The formation of an oxide layer stabilizes the metal against oxidation. The element is found only in chemically combined form in nature. Andrés Manuel del Río
discovered vanadium in 1801 by analyzing a new lead-bearing mineral he called "brown lead," and named the new element erythronium (Greek for "red") since, upon heating, most of its salts turned from their initial color to red. Four years later, however, he was convinced by other scientists that erythronium was identical to chromium. The element was rediscovered in 1831 by Nils Gabriel Sefström
, who named it vanadium after the Germanic goddess
of beauty and fertility, Vanadís (Freyja). Both names were attributed to the wide range of colors found in vanadium compounds. Del Rio's lead mineral was later renamed vanadinite
for its vanadium content.
The element occurs naturally in about 65 different mineral
s and in fossil fuel
deposits. It is produced in China and Russia from steel smelter slag
; other countries produce it either from the 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 tool steels
. The most important industrial vanadium compound, vanadium pentoxide
, is used as a catalyst for the production of sulfuric acid
.
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 enzymes, such as the vanadium bromoperoxidase
of some ocean algae. Vanadium is probably a micronutrient
in mammals, including humans, but its precise role in this regard is unknown.
, a Spanish-born Mexican mineralogist, in 1801. 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") as most of its salts turned red upon heating. In 1805, the 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 only an impure sample of chromium
. Del Río accepted the Collet-Descotils' statement and retracted his claim.
In 1831, the Swedish chemist Nils Gabriel Sefström
rediscovered the element in a new oxide he found while working with iron ores. Later that same year, Friedrich Wöhler
confirmed del Río's earlier work. Sefström chose a name beginning with V, which had not been assigned to any element yet. He called the element vanadium after Old Norse
Vanadís (another name for the Norse
Vanr
goddess Freyja, whose facets include connections to beauty and fertility), because of the many beautifully colored chemical compound
s it produces. In 1831, the geologist George William Featherstonhaugh
suggested that vanadium should be renamed "rionium" after del Río, but this suggestion was not followed.
The isolation of vanadium metal proved difficult. In 1831, Berzelius
reported the production of the metal, but Henry Enfield Roscoe
showed that Berzelius had in fact produced the nitride, vanadium nitride (VN). Roscoe eventually produced the metal in 1867 by reduction of vanadium(II) chloride
, VCl2, with hydrogen
. In 1927, pure vanadium was produced by reducing vanadium pentoxide with calcium
. The first large scale industrial use of vanadium in steels was found in the chassis of the Ford Model T
, inspired by French race cars. Vanadium steel allowed for reduced weight while simultaneously increasing tensile strength
.
s via the r-process
.
, silver-gray metal. Some sources describe vanadium as "soft", perhaps because it is ductile, malleable and not brittle. 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 alkali
s, sulfuric
and hydrochloric acid
s. It is oxidized in air at about 933 K
(660 °C, 1220 °F), although an oxide layer forms even at room temperature.
51V and one radioactive isotope 50V. The latter has a half-life
of 1.5×1017 years and a natural abundance 0.25%. 51V has a nuclear spin of 7/2 which is useful for NMR spectroscopy
. A number of 24 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. All of the remaining radioactive isotopes have half-lives shorter than an hour, most of which are below 10 seconds. At least 4 isotopes have metastable excited states
. Electron capture
is the main decay mode for isotopes lighter than the 51V. For the heavier ones, the most common mode is beta decay
. The electron capture reactions lead to the formation of element 22 (titanium
) isotopes, while for beta decay, it leads to element 24 (chromium
) isotopes.
s. The common oxidation states of vanadium are +2 (lilac), +3 (green), +4 (blue) and +5 (yellow). 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, and substituted derivatives.
The vanadium redox battery
utilizes these oxidation states; conversion of these oxidation states is illustrated by the reduction of a strongly acidic solution of a vanadium(V) compound with zinc dust. The initial yellow color characteristic of the vanadate ion, , is replaced by the blue color of [VO(H2O)5]2+, followed by the green color of [V(H2O)6]3+ and then violet, due to [V(H2O)6]2+.
The most commercially important compound is vanadium pentoxide
, which is used as a catalyst for the production of sulfuric acid. This compound oxidizes sulfur dioxide
to the trioxide
. In this redox reaction, sulfur is oxidized from +4 to +6, and vanadium is reduced from +5 to +3:
The catalyst is regenerated by oxidation with air:
. On acidification, H and are formed, analogous to HP and . The acid dissociation constants for the vanadium and phosphorus series are remarkably similar. In more concentrated solutions many polyvanadates
are formed. Chains, rings and clusters involving tetrahedral vanadium, analogous to the polyphosphate
s, are known. In addition, clusters such as the decavanadates and H, which predominate at pH 4–6, are formed in which compound is octahedral about vanadium.
The correspondence between vanadate and phosphate chemistry can be attributed to the similarity in size and charge of phosphorus(V) and vanadium(V). Orthovanadate
V is used in protein crystallography to study the biochemistry
of phosphate.
Vanadium also forms various peroxo- complexes when treated with hydrogen peroxide. For instance, the yellow oxovanadium(V) ion in acidic hydrogen peroxide solution forms the brick red peroxovanadium(V) ion, VO(O2)2+.
s.
Vanadium's early position in the transition metal
series lead to three rather unusual features of the coordination chemistry of vanadium. Firstly, metallic vanadium has the electronic configuration [Ar]3d34s2, so compounds of vanadium are relatively electron-poor. Consequently, most binary compounds are Lewis acid
s (electron pair acceptors); examples are all the halides forming octahedral adducts with the formula VXnL6−n (X = halide; L = other ligand). Secondly, the vanadium ion is rather large and can achieve coordination numbers higher than 6, as is the case in [V(CN)7]4−. Thirdly, the vanadyl ion, VO2+, is featured in many complexes of vanadium(IV) such as vanadyl acetylacetonate
(V(=O)(acac)2). In this complex, the vanadium is 5-coordinate, 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 bypyramidal geometry, such as VOCl2(NMe3)2.
is a versatile starting reagent and even finds minor applications in organic chemistry. Vanadium carbonyl
, V(CO)6, is a rare example of a metal carbonyl
containing an unpaired electron, but which exists without dimerization. The addition of an electron yields V (isoelectronic with Cr(CO)6), which may be further reduced with sodium in liquid ammonia to yield V (isoelectronic with Fe(CO)5).
s. Economically significant examples include patronite
(VS4), vanadinite
, and carnotite
. Much of the world's vanadium production is sourced from vanadium-bearing magnetite
found in ultramafic gabbro
bodies. Vanadium is mined mostly in South Africa
, north-western China
, and eastern Russia
. In 2010 these three countries mined more than 98% of the 56,000 tonnes of produced vanadium.
Vanadium is also present in bauxite
and in fossil fuel
deposits such as 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, the traces of vanadium may initiate corrosion
in motors and boilers. An estimated 110,000 tonnes of vanadium per year are released into the atmosphere by burning fossil fuels. Vanadium has also been detected spectroscopically in light from the Sun
and some other star
s.
s. Ferrovanadium is produced directly by reducing a mixture of vanadium oxide, iron oxides and iron in an electric furnace. Vanadium-bearing magnetite
iron ore is the main source for the production of vanadium. The vanadium ends up in pig iron
produced from vanadium bearing magnetite. During steel production
, oxygen is blown into the pig iron, oxidizing the carbon and most of the other impurities, forming slag
. Depending on the used ore, the slag contains up to 25% of vanadium.
Vanadium metal is obtained via a multistep process that begins with the roasting of crushed ore with NaCl
or Na2CO3
at about 850 °C to give sodium metavanadate
(NaVO3). An aqueous extract of this solid is acidified to give "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 in use, in all of which vanadium is produced as a byproduct of other processes. 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.
additive. The considerable increase of strength in steel containing small amounts of vanadium was discovered in the beginning of the 20th century. Vanadium forms stable nitrides and carbides, resulting in a significant increase in the strength of the steel. 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 containing steel alloy groups. Vanadium high-carbon steel alloys contain 0.15% to 0.25% vanadium and high speed tool steels
(HSS) have a vanadium content of 1% to 5%. For high speed tool steels, a hardness above HRC 60 can be achieved. HSS steel is used in surgical instruments and tool
s.
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 and high-speed airframes. One of the common alloys is Titanium 6AL-4V, a titanium alloy with 6% aluminium and 4% vanadium.
titanium to steel. 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. Several vanadium alloys show superconducting behavior. The first A15 phase superconductor was a vanadium compound, V3Si, which was discovered in 1952. Vanadium-gallium
tape is used in superconducting
magnets (17.5 tesla
s or 175,000 gauss
). The structure of the superconducting A15 phase of V3Ga is similar to that of the more common Nb3Sn
and Nb3Ti
.
The most common oxide of vanadium, vanadium pentoxide
V2O5, is used as a catalyst in manufacturing sulfuric acid by the contact process
and as an oxidizer in maleic anhydride
production. Vanadium pentoxide is also used in making ceramic
s. Another oxide of vanadium, vanadium dioxide VO2, is used in the production of glass coatings, which blocks infrared radiation (and not visible light) at a specific temperature. Vanadium oxide can be used to induce color centers in corundum
to create simulated alexandrite jewelry, although alexandrite in nature is a chrysoberyl
.
The possibility to use vanadium redox couples in both half-cells, thereby eliminating the problem of cross contamination by diffusion of ions across the membrane is the advantage of vanadium redox rechargeable batteries
. Vanadate
can be used for protecting steel against rust and corrosion by electrochemical conversion coating. 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. It has been proposed by some researchers that a small amount, 40 to 270 ppm, of vanadium in Wootz steel
and Damascus steel
, significantly improves the strength of the material, although it is unclear what the source of the vanadium was.
, and is more important in ocean environments than on land.
are generated by the action of a vanadium dependent bromoperoxidase
. This is a haloperoxidase
in algae which requires bromide and is an absolutely vanadium-dependent enzyme. Most organobromine compounds in the sea ultimately arise via the action of this vanadium bromoperoxidase
.
s (or coelom
ic cells) of Ascidiacea
(sea squirts) in 1911. It is essential to ascidians
and tunicate
s, 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 their blood is up to 10 million times higher than the concentration of vanadium in the seawater around them. Vanadium has been reported in high concentrations in holothurian (sea cucumber) blood, however other researchers have been unable to reproduce these results. There is no evidence that hemovanadin
carries oxygen, in contrast to hemoglobin and hemocyanin, which may also be present in these organisms.
is used by some nitrogen-fixing
micro-organisms, such as Azotobacter
. In this role vanadium replaces more common molybdenum
or iron
, and gives the nitrogenase
slightly different properties.
and related species, accumulate vanadium (up to 500 mg/kg in dry weight). Vanadium is present in the coordination complex, amavadin
, in fungal fruit-bodies. However, the biological importance of the accumulation process is unknown. Toxin functions or peroxidase
enzyme functions have been suggested.
s and chicken
s are also known to require vanadium in very small amounts and deficiencies result in reduced growth and impaired reproduction. Vanadium is a relatively controversial dietary supplement
, primarily for increasing insulin
sensitivity and body-building. Whether it works for the latter purpose has not been proven, and there is some evidence that athletes who take it are merely experiencing a placebo effect
. Vanadyl sulfate may improve glucose control in people with type 2 diabetes. In addition, decavanadate and oxovanadates are species that potentially have many biological activities and that have been successfully used as tools in the comprehension of several biochemical processes.
(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. The National Institute for Occupational Safety and Health
(NIOSH) has recommended that 35 mg/m3 of vanadium be considered immediately dangerous to life and health. This is the exposure level of a chemical that is likely to cause permanent health problems or death.
Vanadium compounds are poorly absorbed through the gastrointestinal system. Inhalation exposures to vanadium and vanadium compounds result primarily in adverse effects on the respiratory system. 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, on liver, on neurological development in rats, and other organs.
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 male and female mice by inhalation in an NTP study, although the interpretation of the results has recently been disputed. Vanadium has not been classified as to carcinogenicity by the United States Environmental Protection Agency
.
Vanadium traces in diesel fuels present a corrosion hazard; it is the main fuel component influencing high temperature corrosion
. During combustion, it oxidizes and reacts with sodium and sulfur, yielding vanadate
compounds with melting points down to 530 °C, which attack the passivation layer on steel, rendering it susceptible to corrosion. The solid vanadium compounds also cause abrasion of engine components.
Chemical element
A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. Familiar examples of elements include carbon, oxygen, aluminum, iron, copper, gold, mercury, and lead.As of November 2011, 118 elements...
with the symbol V and atomic number
Atomic number
In chemistry and physics, the atomic number is the number of protons found in the nucleus of an atom and therefore identical to the charge number of the nucleus. It is conventionally represented by the symbol Z. The atomic number uniquely identifies a chemical element...
23. It is a hard, silvery gray, ductile and malleable transition metal
Transition metal
The term transition metal has two possible meanings:*The IUPAC definition states that a transition metal is "an element whose atom has an incomplete d sub-shell, or which can give rise to cations with an incomplete d sub-shell." Group 12 elements are not transition metals in this definition.*Some...
. The formation of an oxide layer stabilizes the metal against oxidation. The element is found only in chemically combined form in nature. Andrés Manuel del Río
Andrés Manuel del Río
Andrés Manuel del Río Fernández was a Spanish–Mexican scientist and naturalist who discovered the chemical element vanadium.-Education:...
discovered vanadium in 1801 by analyzing a new lead-bearing mineral he called "brown lead," and named the new element erythronium (Greek for "red") since, upon heating, most of its salts turned from their initial color to red. Four years later, however, he was convinced by other scientists that erythronium was identical to chromium. The element was rediscovered in 1831 by Nils Gabriel Sefström
Nils Gabriel Sefström
Nils Gabriel Sefström was a Swedish chemist. Sefström was a student of Berzelius and, when studying the brittleness of steel in 1830, he rediscovered a new chemical element, to which he gave the name vanadium....
, who named it vanadium after the Germanic goddess
Common Germanic deities
The article lists gods and goddesses that may be reconstructed for Proto-Germanic or Common Germanic Migration period paganism, or which figure in both West and North Germanic mythology...
of beauty and fertility, Vanadís (Freyja). Both names were attributed to the wide range of colors found in vanadium compounds. Del Rio's lead mineral was later renamed vanadinite
Vanadinite
Vanadinite is a mineral belonging to the apatite group of phosphates, with the chemical formula Pb53Cl. It is one of the main industrial ores of the metal vanadium and a minor source of lead. A dense, brittle mineral, it is usually found in the form of red hexagonal crystals. It is an uncommon...
for its vanadium content.
The element occurs naturally in about 65 different mineral
Mineral
A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...
s and in fossil fuel
Fossil fuel
Fossil fuels are fuels formed by natural processes such as anaerobic decomposition of buried dead organisms. The age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years...
deposits. It is produced in China and Russia from steel smelter slag
Slag
Slag is a partially vitreous by-product of smelting ore to separate the metal fraction from the unwanted fraction. It can usually be considered to be a mixture of metal oxides and silicon dioxide. However, slags can contain metal sulfides and metal atoms in the elemental form...
; other countries produce it either from the flue dust of heavy oil, or as a byproduct of uranium mining. It is mainly used to produce specialty steel alloy
Alloy
An alloy is a mixture or metallic solid solution composed of two or more elements. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may or may not be homogeneous in distribution, depending on thermal history...
s such as high speed tool steels
High speed steel
High speed steelMost copyeditors today would tend to choose to style the unit adjective high-speed with a hyphen, rendering the full term as high-speed steel, and this styling is not uncommon . However, it is true that in the metalworking industries the styling high speed steel is long-established...
. The most important industrial vanadium compound, vanadium pentoxide
Vanadium(V) oxide
Vanadium oxide is the chemical compound with the formula V2O5. Commonly known as vanadium pentoxide, this brown/yellow solid is the most stable and common compound of vanadium. Upon heating it reversibly loses oxygen...
, is used as a catalyst for the production of sulfuric acid
Sulfuric acid
Sulfuric acid is a strong mineral acid with the molecular formula . Its historical name is oil of vitriol. Pure sulfuric acid is a highly corrosive, colorless, viscous liquid. The salts of sulfuric acid are called sulfates...
.
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 enzymes, such as the vanadium bromoperoxidase
Vanadium bromoperoxidase
Vanadium bromoperoxidase is a haloperoxidase, used to synthesize halogenated organic compounds associated with defense and pigmentation in seaweeds and marine algae. It is the source of the bulk of organobromine compounds in the ocean...
of some ocean algae. Vanadium is probably a micronutrient
Micronutrient
Micronutrients are nutrients required by humans and other living things throughout life in small quantities to orchestrate a whole range of physiological functions, but which the organism itself cannot produce. For people, they include dietary trace minerals in amounts generally less than 100...
in mammals, including humans, but its precise role in this regard is unknown.
History
Vanadium was originally discovered by Andrés Manuel del RíoAndrés Manuel del Río
Andrés Manuel del Río Fernández was a Spanish–Mexican scientist and naturalist who discovered the chemical element vanadium.-Education:...
, a Spanish-born Mexican mineralogist, in 1801. Del Río extracted the element from a sample of Mexican "brown lead" ore, later named vanadinite
Vanadinite
Vanadinite is a mineral belonging to the apatite group of phosphates, with the chemical formula Pb53Cl. It is one of the main industrial ores of the metal vanadium and a minor source of lead. A dense, brittle mineral, it is usually found in the form of red hexagonal crystals. It is an uncommon...
. 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") as most of its salts turned red upon heating. In 1805, the French chemist Hippolyte Victor Collet-Descotils, backed by del Río's friend Baron Alexander von Humboldt
Alexander von Humboldt
Friedrich Wilhelm Heinrich Alexander Freiherr von Humboldt was a German naturalist and explorer, and the younger brother of the Prussian minister, philosopher and linguist Wilhelm von Humboldt...
, incorrectly declared that del Río's new element was only an impure sample of chromium
Chromium
Chromium is a chemical element which has the symbol Cr and atomic number 24. It is the first element in Group 6. It is a steely-gray, lustrous, hard metal that takes a high polish and has a high melting point. It is also odorless, tasteless, and malleable...
. Del Río accepted the Collet-Descotils' statement and retracted his claim.
In 1831, the Swedish chemist Nils Gabriel Sefström
Nils Gabriel Sefström
Nils Gabriel Sefström was a Swedish chemist. Sefström was a student of Berzelius and, when studying the brittleness of steel in 1830, he rediscovered a new chemical element, to which he gave the name vanadium....
rediscovered the element in a new oxide he found while working with iron ores. Later that same year, Friedrich Wöhler
Friedrich Wöhler
Friedrich Wöhler was a German chemist, best known for his synthesis of urea, but also the first to isolate several chemical elements.-Biography:He was born in Eschersheim, which belonged to aau...
confirmed del Río's earlier work. Sefström chose a name beginning with V, which had not been assigned to any element yet. He called the element vanadium after Old Norse
Old Norse
Old Norse is a North Germanic language that was spoken by inhabitants of Scandinavia and inhabitants of their overseas settlements during the Viking Age, until about 1300....
Vanadís (another name for the Norse
Norse mythology
Norse mythology, a subset of Germanic mythology, is the overall term for the myths, legends and beliefs about supernatural beings of Norse pagans. It flourished prior to the Christianization of Scandinavia, during the Early Middle Ages, and passed into Nordic folklore, with some aspects surviving...
Vanr
Vanir
In Norse mythology, the Vanir are a group of gods associated with fertility, wisdom and the ability to see the future. The Vanir are one of two groups of gods and are the namesake of the location Vanaheimr . After the Æsir–Vanir War, the Vanir became a subgroup of the Æsir...
goddess Freyja, whose facets include connections to beauty and fertility), because of the many beautifully colored chemical compound
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
s it produces. In 1831, the geologist George William Featherstonhaugh
George William Featherstonhaugh
George William Featherstonhaugh FRS was a British geologist and geographer who initiated the Albany and Schenectady Railroad and was a surveyor of the Louisiana Purchase for the US Government....
suggested that vanadium should be renamed "rionium" after del Río, but this suggestion was not followed.
Jöns Jakob Berzelius
Jöns Jacob Berzelius was a Swedish chemist. He worked out the modern technique of chemical formula notation, and is together with John Dalton, Antoine Lavoisier, and Robert Boyle considered a father of modern chemistry...
reported the production of the metal, but Henry Enfield Roscoe
Henry Enfield Roscoe
Sir Henry Enfield Roscoe, FRS was an English chemist. He is particularly noted for early work on vanadium and for photochemical studies.- Life and work :...
showed that Berzelius had in fact produced the nitride, vanadium nitride (VN). Roscoe eventually produced the metal in 1867 by reduction of vanadium(II) chloride
Vanadium(II) chloride
Vanadium chloride is the inorganic compound with the formula VCl2. This purple solid is the most reduced vanadium chloride. Like other metal dihalides, it is a polymer...
, VCl2, with hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
. In 1927, pure vanadium was produced by reducing vanadium pentoxide with calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
. The first large scale industrial use of vanadium in steels was found in the chassis of the Ford Model T
Ford Model T
The Ford Model T is an automobile that was produced by Henry Ford's Ford Motor Company from September 1908 to May 1927...
, inspired by French race cars. Vanadium steel allowed for reduced weight while simultaneously increasing tensile strength
Tensile strength
Ultimate tensile strength , often shortened to tensile strength or ultimate strength, is the maximum stress that a material can withstand while being stretched or pulled before necking, which is when the specimen's cross-section starts to significantly contract...
.
Creation
The stable form of vanadium is created in supernovaSupernova
A supernova is a stellar explosion that is more energetic than a nova. It is pronounced with the plural supernovae or supernovas. Supernovae are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months...
s via the r-process
R-process
The r-process is a nucleosynthesis process, likely occurring in core-collapse supernovae responsible for the creation of approximately half of the neutron-rich atomic nuclei that are heavier than iron. The process entails a succession of rapid neutron captures on seed nuclei, typically Ni-56,...
.
Characteristics
Vanadium is a hard, ductileDuctility
In materials science, ductility is a solid material's ability to deform under tensile stress; this is often characterized by the material's ability to be stretched into a wire. Malleability, a similar property, is a material's ability to deform under compressive stress; this is often characterized...
, silver-gray metal. Some sources describe vanadium as "soft", perhaps because it is ductile, malleable and not brittle. Vanadium is harder than most metals and steels (see Hardnesses of the elements (data page) and iron). It has good resistance to corrosion
Corrosion
Corrosion is the disintegration of an engineered material into its constituent atoms due to chemical reactions with its surroundings. In the most common use of the word, this means electrochemical oxidation of metals in reaction with an oxidant such as oxygen...
and it is stable against alkali
Alkali
In chemistry, an alkali is a basic, ionic salt of an alkali metal or alkaline earth metal element. Some authors also define an alkali as a base that dissolves in water. A solution of a soluble base has a pH greater than 7. The adjective alkaline is commonly used in English as a synonym for base,...
s, sulfuric
Sulfuric acid
Sulfuric acid is a strong mineral acid with the molecular formula . Its historical name is oil of vitriol. Pure sulfuric acid is a highly corrosive, colorless, viscous liquid. The salts of sulfuric acid are called sulfates...
and hydrochloric acid
Hydrochloric acid
Hydrochloric acid is a solution of hydrogen chloride in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid....
s. It is oxidized in air at about 933 K
Kelvin
The kelvin is a unit of measurement for temperature. It is one of the seven base units in the International System of Units and is assigned the unit symbol K. The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all...
(660 °C, 1220 °F), although an oxide layer forms even at room temperature.
Isotopes
Naturally occurring vanadium is composed of one stable isotopeIsotope
Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...
51V and one radioactive isotope 50V. The latter has a half-life
Half-life
Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...
of 1.5×1017 years and a natural abundance 0.25%. 51V has a nuclear spin of 7/2 which is useful for NMR spectroscopy
NMR spectroscopy
Nuclear magnetic resonance spectroscopy, most commonly known as NMR spectroscopy, is a research technique that exploits the magnetic properties of certain atomic nuclei to determine physical and chemical properties of atoms or the molecules in which they are contained...
. A number of 24 artificial radioisotopes have been characterized, ranging in mass number
Mass number
The mass number , also called atomic mass number or nucleon number, is the total number of protons and neutrons in an atomic nucleus. Because protons and neutrons both are baryons, the mass number A is identical with the baryon number B as of the nucleus as of the whole atom or ion...
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. All of the remaining radioactive isotopes have half-lives shorter than an hour, most of which are below 10 seconds. At least 4 isotopes have metastable excited states
Nuclear isomer
A nuclear isomer is a metastable state of an atomic nucleus caused by the excitation of one or more of its nucleons . "Metastable" refers to the fact that these excited states have half-lives more than 100 to 1000 times the half-lives of the other possible excited nuclear states...
. Electron capture
Electron capture
Electron capture is a process in which a proton-rich nuclide absorbs an inner atomic electron and simultaneously emits a neutrino...
is the main decay mode for isotopes lighter than the 51V. For the heavier ones, the most common mode is beta decay
Beta decay
In nuclear physics, beta decay is a type of radioactive decay in which a beta particle is emitted from an atom. There are two types of beta decay: beta minus and beta plus. In the case of beta decay that produces an electron emission, it is referred to as beta minus , while in the case of a...
. The electron capture reactions lead to the formation of element 22 (titanium
Titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....
) isotopes, while for beta decay, it leads to element 24 (chromium
Chromium
Chromium is a chemical element which has the symbol Cr and atomic number 24. It is the first element in Group 6. It is a steely-gray, lustrous, hard metal that takes a high polish and has a high melting point. It is also odorless, tasteless, and malleable...
) isotopes.
Chemistry and compounds
The chemistry of vanadium is noteworthy for the accessibility of four adjacent oxidation stateOxidation state
In chemistry, the oxidation state is an indicator of the degree of oxidation of an atom in a chemical compound. The formal oxidation state is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic. Oxidation states are typically represented by...
s. The common oxidation states of vanadium are +2 (lilac), +3 (green), +4 (blue) and +5 (yellow). Vanadium(II) compounds are reducing agents, and vanadium(V) compounds are oxidizing agents. Vanadium(IV) compounds often exist as vanadyl
Vanadyl ion
The vanadyl or oxovanadium cation, [VO]2+, is a blue-coloured vanadium oxocation. It is one of the most stable diatomic ions known and forms a wide range of complexes.-Compounds containing the vanadyl ion:* vanadyl, VO2...
derivatives which contain the VO2+ center.
Ammonium metavanadate
Ammonium metavanadate, NH4VO3, is a yellow crystalline solid which is water soluble inorganic acid that acts as insulin mimic. It functions as a catalyst to certain reactions and is known to have toxic effects in certain species. It has been found in slags and fly ash from coal burning which has...
(NH4VO3) can be successively reduced with elemental zinc
Zinc
Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
to obtain the different colors of vanadium in these four oxidation states. Lower oxidation states occur in compounds such as V(CO)6, and substituted derivatives.
The vanadium redox battery
Vanadium redox battery
The vanadium redox battery is a type of rechargeable flow battery that employs vanadium ions in different oxidation states to store chemical potential energy...
utilizes these oxidation states; conversion of these oxidation states is illustrated by the reduction of a strongly acidic solution of a vanadium(V) compound with zinc dust. The initial yellow color characteristic of the vanadate ion, , is replaced by the blue color of [VO(H2O)5]2+, followed by the green color of [V(H2O)6]3+ and then violet, due to [V(H2O)6]2+.
The most commercially important compound is vanadium pentoxide
Vanadium(V) oxide
Vanadium oxide is the chemical compound with the formula V2O5. Commonly known as vanadium pentoxide, this brown/yellow solid is the most stable and common compound of vanadium. Upon heating it reversibly loses oxygen...
, which is used as a catalyst for the production of sulfuric acid. This compound oxidizes sulfur dioxide
Sulfur dioxide
Sulfur dioxide is the chemical compound with the formula . It is released by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide unless the sulfur compounds are removed before burning the fuel...
to the trioxide
Sulfur trioxide
Sulfur trioxide is the chemical compound with the formula SO3. In the gaseous form, this species is a significant pollutant, being the primary agent in acid rain. It is prepared on massive scales as a precursor to sulfuric acid.-Structure and bonding:Gaseous SO3 is a trigonal planar molecule of...
. In this redox reaction, sulfur is oxidized from +4 to +6, and vanadium is reduced from +5 to +3:
- V2O5 + 2 SO2 → V2O3 + 2 SO3
The catalyst is regenerated by oxidation with air:
- V2O3 + O2 → V2O5
Oxy and oxo compounds
The oxyanion chemistry of vanadium(V) is complex. The vanadate ion, , is present in dilute solutions at high pHPH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
. On acidification, H and are formed, analogous to HP and . The acid dissociation constants for the vanadium and phosphorus series are remarkably similar. In more concentrated solutions many polyvanadates
Vanadate
In chemistry, a vanadate is a compound containing an oxoanion of vanadium generally in its highest oxidation state of +5. The simplest vanadate ion is the tetrahedral, orthovanadate, VO43− anion, which is present in e.g. sodium orthovanadate and in solutions of V2O5 in strong base...
are formed. Chains, rings and clusters involving tetrahedral vanadium, analogous to the polyphosphate
Polyphosphate
Triphosphates are salts or esters of polymeric oxyanions formed from tetrahedral PO4 structural units linked together by sharing oxygen atoms. When two corners are shared the polyphosphate may have a linear chain structure or a cyclic ring structure. In biology the polyphosphate esters AMP, ADP...
s, are known. In addition, clusters such as the decavanadates and H, which predominate at pH 4–6, are formed in which compound is octahedral about vanadium.
The correspondence between vanadate and phosphate chemistry can be attributed to the similarity in size and charge of phosphorus(V) and vanadium(V). Orthovanadate
Sodium orthovanadate
Sodium orthovanadate is the chemical compound Na3VO4 and contains the tetrahedral VO43−. It is an inhibitor of protein tyrosine phosphatases, alkaline phosphatases and a number of ATPases, most likely acting as a phosphate analogue...
V is used in protein crystallography to study the biochemistry
Biochemistry
Biochemistry, sometimes called biological chemistry, is the study of chemical processes in living organisms, including, but not limited to, living matter. Biochemistry governs all living organisms and living processes...
of phosphate.
Vanadium also forms various peroxo- complexes when treated with hydrogen peroxide. For instance, the yellow oxovanadium(V) ion in acidic hydrogen peroxide solution forms the brick red peroxovanadium(V) ion, VO(O2)2+.
Halide compounds
Several halides are known for oxidation states +2, +3 and +4. VCl4 is the most important commercially. This liquid is mainly used as a catalyst for polymerization of dieneDiene
In organic chemistry a diene or diolefin is a hydrocarbon that contains two carbon double bonds.Conjugated dienes are functional groups, with a general formula of CnH2n-2. Dienes and alkynes are functional isomers...
s.
Coordination compounds
Transition metal
The term transition metal has two possible meanings:*The IUPAC definition states that a transition metal is "an element whose atom has an incomplete d sub-shell, or which can give rise to cations with an incomplete d sub-shell." Group 12 elements are not transition metals in this definition.*Some...
series lead to three rather unusual features of the coordination chemistry of vanadium. Firstly, metallic vanadium has the electronic configuration [Ar]3d34s2, so compounds of vanadium are relatively electron-poor. Consequently, most binary compounds are Lewis acid
Lewis acid
]The term Lewis acid refers to a definition of acid published by Gilbert N. Lewis in 1923, specifically: An acid substance is one which can employ a lone pair from another molecule in completing the stable group of one of its own atoms. Thus, H+ is a Lewis acid, since it can accept a lone pair,...
s (electron pair acceptors); examples are all the halides forming octahedral adducts with the formula VXnL6−n (X = halide; L = other ligand). Secondly, the vanadium ion is rather large and can achieve coordination numbers higher than 6, as is the case in [V(CN)7]4−. Thirdly, the vanadyl ion, VO2+, is featured in many complexes of vanadium(IV) such as vanadyl acetylacetonate
Vanadyl acetylacetonate
Vanadyl acetylacetonate is the chemical compound with the formula VO2. This blue-green coordination complex consists of the vanadyl group, VO2+, bound to two acetylacetonate anions, acac−. Like other charge-neutral acetylacetonates, this complex is soluble in organic solvents.-Synthesis:The...
(V(=O)(acac)2). In this complex, the vanadium is 5-coordinate, 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 bypyramidal geometry, such as VOCl2(NMe3)2.
Organometallic compounds
Organometallic chemistry of vanadium is well developed, but organometallic compounds are of minor commercial significance. Vanadocene dichlorideVanadocene dichloride
Vanadocene dichloride, dichloro bisvanadium is 2VCl2 . It is a structural analoque of titanocene dichloride but with vanadium instead of titanium....
is a versatile starting reagent and even finds minor applications in organic chemistry. Vanadium carbonyl
Vanadium carbonyl
Vanadium carbonyl, also known as vanadium hexacarbonyl, is the inorganic compound with the formula V6. This highly reactive species is noteworthy from theoretical and scholarly perspectives. It is a rare isolable homoleptic metal carbonyl that is paramagnetic...
, V(CO)6, is a rare example of a metal carbonyl
Metal carbonyl
Metal carbonyls are coordination complexes of transition metals with carbon monoxide ligands. These complexes may be homoleptic, that is containing only CO ligands, such as nickel carbonyl , but more commonly metal carbonyls contain a mix of ligands, such as Re3Cl...
containing an unpaired electron, but which exists without dimerization. The addition of an electron yields V (isoelectronic with Cr(CO)6), which may be further reduced with sodium in liquid ammonia to yield V (isoelectronic with Fe(CO)5).
Occurrence
Metallic vanadium is not found in nature, but is known to exist in about 65 different mineralMineral
A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...
s. Economically significant examples include patronite
Patronite
Patronite is the vanadium sulfide mineral with formula VS4. The material is usually described as V4+2. Structurally, it is a "linear-chain" compound with alternating bonding and nonbonding contacts between the vanadium centers...
(VS4), vanadinite
Vanadinite
Vanadinite is a mineral belonging to the apatite group of phosphates, with the chemical formula Pb53Cl. It is one of the main industrial ores of the metal vanadium and a minor source of lead. A dense, brittle mineral, it is usually found in the form of red hexagonal crystals. It is an uncommon...
, and carnotite
Carnotite
Carnotite is a potassium uranium vanadate radioactive mineral with chemical formula: K222·3H2O. The water content can vary and small amounts of calcium, barium, magnesium, iron, and sodium are often present.-Occurrence:...
. Much of the world's vanadium production is sourced from vanadium-bearing magnetite
Magnetite
Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. The chemical IUPAC name is iron oxide and the common chemical name is ferrous-ferric oxide. The formula for magnetite may also be written as FeO·Fe2O3, which is one part...
found in ultramafic gabbro
Gabbro
Gabbro refers to a large group of dark, coarse-grained, intrusive mafic igneous rocks chemically equivalent to basalt. The rocks are plutonic, formed when molten magma is trapped beneath the Earth's surface and cools into a crystalline mass....
bodies. Vanadium is mined mostly in South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
, north-western China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
, and eastern Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
. In 2010 these three countries mined more than 98% of the 56,000 tonnes of produced vanadium.
Vanadium is also present in bauxite
Bauxite
Bauxite is an aluminium ore and is the main source of aluminium. This form of rock consists mostly of the minerals gibbsite Al3, boehmite γ-AlO, and diaspore α-AlO, in a mixture with the two iron oxides goethite and hematite, the clay mineral kaolinite, and small amounts of anatase TiO2...
and in fossil fuel
Fossil fuel
Fossil fuels are fuels formed by natural processes such as anaerobic decomposition of buried dead organisms. The age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years...
deposits such as crude oil, coal
Coal
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...
, oil shale
Oil shale
Oil shale, an organic-rich fine-grained sedimentary rock, contains significant amounts of kerogen from which liquid hydrocarbons called shale oil can be produced...
and tar
Tar
Tar is modified pitch produced primarily from the wood and roots of pine by destructive distillation under pyrolysis. Production and trade in tar was a major contributor in the economies of Northern Europe and Colonial America. Its main use was in preserving wooden vessels against rot. The largest...
sands. In crude oil, concentrations up to 1200 ppm have been reported. When such oil products are burned, the traces of vanadium may initiate corrosion
Corrosion
Corrosion is the disintegration of an engineered material into its constituent atoms due to chemical reactions with its surroundings. In the most common use of the word, this means electrochemical oxidation of metals in reaction with an oxidant such as oxygen...
in motors and boilers. An estimated 110,000 tonnes of vanadium per year are released into the atmosphere by burning fossil fuels. Vanadium has also been detected spectroscopically in light from the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
and some other star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
s.
Production
Most vanadium is used as an alloy called ferrovanadium as an additive to improve steelSteel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
s. Ferrovanadium is produced directly by reducing a mixture of vanadium oxide, iron oxides and iron in an electric furnace. Vanadium-bearing magnetite
Magnetite
Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. The chemical IUPAC name is iron oxide and the common chemical name is ferrous-ferric oxide. The formula for magnetite may also be written as FeO·Fe2O3, which is one part...
iron ore is the main source for the production of vanadium. The vanadium ends up in pig iron
Pig iron
Pig iron is the intermediate product of smelting iron ore with a high-carbon fuel such as coke, usually with limestone as a flux. Charcoal and anthracite have also been used as fuel...
produced from vanadium bearing magnetite. During steel production
Basic oxygen steelmaking
Basic oxygen steelmaking , also known as Linz-Donawitz-Verfahren steelmaking or the oxygen converter process is a method of primary steelmaking in which carbon-rich molten pig iron is made into steel. Blowing oxygen through molten pig iron lowers the carbon content of the alloy and changes it into...
, oxygen is blown into the pig iron, oxidizing the carbon and most of the other impurities, forming slag
Slag
Slag is a partially vitreous by-product of smelting ore to separate the metal fraction from the unwanted fraction. It can usually be considered to be a mixture of metal oxides and silicon dioxide. However, slags can contain metal sulfides and metal atoms in the elemental form...
. Depending on the used ore, the slag contains up to 25% of vanadium.
Vanadium metal is obtained via a multistep process that begins with the roasting of crushed ore with NaCl
Sodium chloride
Sodium chloride, also known as salt, common salt, table salt or halite, is an inorganic compound with the formula NaCl. Sodium chloride is the salt most responsible for the salinity of the ocean and of the extracellular fluid of many multicellular organisms...
or Na2CO3
Sodium carbonate
Sodium carbonate , Na2CO3 is a sodium salt of carbonic acid. It most commonly occurs as a crystalline heptahydrate, which readily effloresces to form a white powder, the monohydrate. Sodium carbonate is domestically well-known for its everyday use as a water softener. It can be extracted from the...
at about 850 °C to give sodium metavanadate
Sodium metavanadate
Sodium metavanadate is a yellow solid which is soluble in water. Its use is limited to its hygroscopic property. Its natural forms include mineral metamunirite and a dihydrate, munirite. Both are very rare, metamunirite is now known only from V- and U-bearing sandstone formations of...
(NaVO3). An aqueous extract of this solid is acidified to give "red cake", a polyvanadate salt, which is reduced with calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
metal. As an alternative for small scale production, vanadium pentoxide is reduced with hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
or magnesium
Magnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
. Many other methods are also in use, in all of which vanadium is produced as a byproduct of other processes. Purification of vanadium is possible by the crystal bar process
Crystal bar process
The crystal bar process was developed by Anton Eduard van Arkel and Jan Hendrik de Boer in 1925. This process was the first industrial process for the commercial production of pure ductile metallic zirconium. It is used in the production of small quantities of ultra-pure titanium and zirconium...
developed by Anton Eduard van Arkel
Anton Eduard van Arkel
Anton Eduard van Arkel, was a Dutch chemist.-See also:*Crystal bar process*Hafnium*Jan Hendrik de Boer*Titanium*Van Arkel-Ketelaar triangle-References:...
and Jan Hendrik de Boer
Jan Hendrik de Boer
Jan Hendrik de Boer was a Dutch physicist and chemist.De Boer was born in Ruinen, now De Wolden, and died in 's-Gravenzande...
in 1925. It involves the formation of the metal iodide, in this example vanadium(III) iodide
Vanadium(III) iodide
Vanadium iodide is the inorganic compound with the formula VI3. This paramagnetic solid is generated by the reaction of vanadium powder with iodine at around 500 °C...
, and the subsequent decomposition to yield pure metal.
- 2 V + 3 I2 2 VI3
Applications
Alloys
Approximately 85% of vanadium produced is used as ferrovanadium or as a steelSteel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
additive. The considerable increase of strength in steel containing small amounts of vanadium was discovered in the beginning of the 20th century. Vanadium forms stable nitrides and carbides, resulting in a significant increase in the strength of the steel. From that time on vanadium steel was used for applications in axle
Axle
An axle is a central shaft for a rotating wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to its surroundings, with the wheels rotating around the axle. In the former case, bearings or bushings are provided at the mounting points where the axle...
s, bicycle frames, crankshaft
Crankshaft
The crankshaft, sometimes casually abbreviated to crank, is the part of an engine which translates reciprocating linear piston motion into rotation...
s, gears, and other critical components. There are two groups of vanadium containing steel alloy groups. Vanadium high-carbon steel alloys contain 0.15% to 0.25% vanadium and high speed tool steels
High speed steel
High speed steelMost copyeditors today would tend to choose to style the unit adjective high-speed with a hyphen, rendering the full term as high-speed steel, and this styling is not uncommon . However, it is true that in the metalworking industries the styling high speed steel is long-established...
(HSS) have a vanadium content of 1% to 5%. For high speed tool steels, a hardness above HRC 60 can be achieved. HSS steel is used in surgical instruments and tool
Tool
A tool is a device that can be used to produce an item or achieve a task, but that is not consumed in the process. Informally the word is also used to describe a procedure or process with a specific purpose. Tools that are used in particular fields or activities may have different designations such...
s.
Vanadium stabilizes the beta form of titanium and increases the strength and temperature stability of titanium. Mixed with aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
in titanium
Titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....
alloys it is used in jet engine
Jet engine
A jet engine is a reaction engine that discharges a fast moving jet to generate thrust by jet propulsion and in accordance with Newton's laws of motion. This broad definition of jet engines includes turbojets, turbofans, rockets, ramjets, pulse jets...
s and high-speed airframes. One of the common alloys is Titanium 6AL-4V, a titanium alloy with 6% aluminium and 4% vanadium.
Other uses
Vanadium is compatible with iron and titanium, therefore vanadium foil is used in claddingCladding (metalworking)
Cladding is the bonding together of dissimilar metals. It is distinct from welding or gluing as a method to fasten the metals together. Cladding is often achieved by extruding two metals through a die as well as pressing or rolling sheets together under high pressure.The United States Mint uses...
titanium to steel. The moderate thermal neutron-capture cross-section
Neutron capture
Neutron capture is a kind of nuclear reaction in which an atomic nucleus collides with one or more neutrons and they merge to form a heavier nucleus. Since neutrons have no electric charge they can enter a nucleus more easily than positively charged protons, which are repelled...
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. Several vanadium alloys show superconducting behavior. The first A15 phase superconductor was a vanadium compound, V3Si, which was discovered in 1952. Vanadium-gallium
Vanadium-gallium
Vanadium-gallium a superconducting alloy of vanadium and gallium often used for the high field insert coils of superconducting electromagnets.Vanadium-gallium tape is used in superconducting magnets...
tape is used in superconducting
Superconductivity
Superconductivity is a phenomenon of exactly zero electrical resistance occurring in certain materials below a characteristic temperature. It was discovered by Heike Kamerlingh Onnes on April 8, 1911 in Leiden. Like ferromagnetism and atomic spectral lines, superconductivity is a quantum...
magnets (17.5 tesla
Tesla (unit)
The tesla is the SI derived unit of magnetic field B . One tesla is equal to one weber per square meter, and it was defined in 1960 in honour of the inventor, physicist, and electrical engineer Nikola Tesla...
s or 175,000 gauss
Gauss (unit)
The gauss, abbreviated as G, is the cgs unit of measurement of a magnetic field B , named after the German mathematician and physicist Carl Friedrich Gauss. One gauss is defined as one maxwell per square centimeter; it equals 1 tesla...
). The structure of the superconducting A15 phase of V3Ga is similar to that of the more common Nb3Sn
Niobium-tin
Niobium-tin or triniobium-tin is a metallic chemical compound of niobium and tin , used industrially as a type II superconductor. This intermetallic compoundis a A15 phases superconductor...
and Nb3Ti
Niobium-titanium
Niobium-titanium is an alloy of niobium and titanium, used industrially as a type II superconductor wire for superconducting magnets...
.
The most common oxide of vanadium, vanadium pentoxide
Vanadium(V) oxide
Vanadium oxide is the chemical compound with the formula V2O5. Commonly known as vanadium pentoxide, this brown/yellow solid is the most stable and common compound of vanadium. Upon heating it reversibly loses oxygen...
V2O5, is used as a catalyst in manufacturing sulfuric acid by the contact process
Contact process
The contact process is the current method of producing sulphuric acid in the high concentrations needed for industrial processes. Platinum was formerly employed as a catalyst for the reaction, but as it is susceptible to poisoning by arsenic impurities in the sulfur feedstock, vanadium oxide is...
and as an oxidizer in maleic anhydride
Maleic anhydride
Maleic anhydride is an organic compound with the formula C2H22O. It is the acid anhydride of maleic acid and in its pure state it is a colourless or white solid with an acrid odour....
production. Vanadium pentoxide is also used in making ceramic
Ceramic
A ceramic is an inorganic, nonmetallic solid prepared by the action of heat and subsequent cooling. Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous...
s. Another oxide of vanadium, vanadium dioxide VO2, is used in the production of glass coatings, which blocks infrared radiation (and not visible light) at a specific temperature. Vanadium oxide can be used to induce color centers in corundum
Corundum
Corundum is a crystalline form of aluminium oxide with traces of iron, titanium and chromium. It is a rock-forming mineral. It is one of the naturally clear transparent materials, but can have different colors when impurities are present. Transparent specimens are used as gems, called ruby if red...
to create simulated alexandrite jewelry, although alexandrite in nature is a chrysoberyl
Chrysoberyl
The mineral or gemstone chrysoberyl is an aluminate of beryllium with the formula BeAl2O4. The name chrysoberyl is derived from the Greek words χρυσός chrysos and βήρυλλος beryllos, meaning "a gold-white spar". Despite the similarity of their names, chrysoberyl and beryl are two completely...
.
The possibility to use vanadium redox couples in both half-cells, thereby eliminating the problem of cross contamination by diffusion of ions across the membrane is the advantage of vanadium redox rechargeable batteries
Vanadium redox battery
The vanadium redox battery is a type of rechargeable flow battery that employs vanadium ions in different oxidation states to store chemical potential energy...
. Vanadate
Vanadate
In chemistry, a vanadate is a compound containing an oxoanion of vanadium generally in its highest oxidation state of +5. The simplest vanadate ion is the tetrahedral, orthovanadate, VO43− anion, which is present in e.g. sodium orthovanadate and in solutions of V2O5 in strong base...
can be used for protecting steel against rust and corrosion by electrochemical conversion coating. 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
Lithium cobalt oxide
Lithium cobalt oxide is a chemical compound commonly used in the positive electrodes of lithium-ion batteries. The structure of LiCoO2 is known theoretically and has been confirmed with techniques like x-ray diffraction, electron microscopy, neutron powder diffraction, and EXAFS: it consists of...
cathode. It has been proposed by some researchers that a small amount, 40 to 270 ppm, of vanadium in Wootz steel
Wootz steel
Wootz steel is a steel characterized by a pattern of bands or sheets of micro carbides within a tempered martensite or pearlite matrix. It was developed in India around 300 BCE...
and Damascus steel
Damascus steel
Damascus steel was a term used by several Western cultures from the Medieval period onward to describe a type of steel used in swordmaking from about 300 BCE to 1700 CE. These swords are characterized by distinctive patterns of banding and mottling reminiscent of flowing water...
, significantly improves the strength of the material, although it is unclear what the source of the vanadium was.
Biological role
Vanadium plays a very limited role in biologyBiology
Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy. Biology is a vast subject containing many subdivisions, topics, and disciplines...
, and is more important in ocean environments than on land.
Bromoperoxidases in algae
Organobromine compounds in a number of species of marine algaeAlgae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
are generated by the action of a vanadium dependent bromoperoxidase
Bromoperoxidase
Bromoperoxidases are enzymes that catalyse the bromination of hydrocarbons. The enzymes accomplish this reaction via the following reaction:Related chloroperoxidase enzymes effect chlorination....
. This is a haloperoxidase
Haloperoxidase
Haloperoxidases are peroxidases that are able to mediate the oxidation of halides by hydrogen peroxide. Both halides and hydrogen peroxide are widely available in the environment....
in algae which requires bromide and is an absolutely vanadium-dependent enzyme. Most organobromine compounds in the sea ultimately arise via the action of this vanadium bromoperoxidase
Vanadium bromoperoxidase
Vanadium bromoperoxidase is a haloperoxidase, used to synthesize halogenated organic compounds associated with defense and pigmentation in seaweeds and marine algae. It is the source of the bulk of organobromine compounds in the ocean...
.
Vanadium accumulation in tunicates and ascidians
German chemist Martin Henze discovered vanadium in the blood cellBlood cell
A blood cell, also called a hematocyte, is a cell normally found in blood. In mammals, these fall into three general categories:* red blood cells — Erythrocytes* white blood cells — Leukocytes* platelets — Thrombocytes...
s (or coelom
Coelom
The coelom is a fluid-filled cavity formed within the mesoderm. Coeloms developed in triploblasts but were subsequently lost in several lineages. Loss of coelom is correlated with reduction in body size...
ic cells) of Ascidiacea
Ascidiacea
Ascidiacea is a class in the Tunicata subphylum of sac-like marine invertebrate filter feeders. Ascidians are characterized by a tough outer "tunic" made of the polysaccharide tunicin, as compared to other tunicates which are less rigid.Ascidians are found all over the world, usually in shallow...
(sea squirts) in 1911. It is essential to ascidians
Ascidiacea
Ascidiacea is a class in the Tunicata subphylum of sac-like marine invertebrate filter feeders. Ascidians are characterized by a tough outer "tunic" made of the polysaccharide tunicin, as compared to other tunicates which are less rigid.Ascidians are found all over the world, usually in shallow...
and tunicate
Tunicate
Tunicates, also known as urochordates, are members of the subphylum Tunicata, previously known as Urochordata, a group of underwater saclike filter feeders with incurrent and excurrent siphons that is classified within the phylum Chordata. While most tunicates live on the ocean floor, others such...
s, 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 their blood is up to 10 million times higher than the concentration of vanadium in the seawater around them. Vanadium has been reported in high concentrations in holothurian (sea cucumber) blood, however other researchers have been unable to reproduce these results. There is no evidence that hemovanadin
Hemovanadin
Hemovanadin is used to refer to the pale green vanabin proteins found in the blood cells, called vanadocytes, of ascidians and other organisms...
carries oxygen, in contrast to hemoglobin and hemocyanin, which may also be present in these organisms.
Nitrogen fixation
A vanadium nitrogenaseVanadium nitrogenase
Vanadium nitrogenase is a key enzyme for nitrogen fixation found in nitrogen-fixing bacteria, and is used as an alternative to molybdenum nitrogenase when molybdenum is unavailable. An important component of the nitrogen cycle, vanadium nitrogenase converts nitrogen gas to ammonia, thereby making...
is used by some nitrogen-fixing
Nitrogen fixation
Nitrogen fixation is the natural process, either biological or abiotic, by which nitrogen in the atmosphere is converted into ammonia . This process is essential for life because fixed nitrogen is required to biosynthesize the basic building blocks of life, e.g., nucleotides for DNA and RNA and...
micro-organisms, such as Azotobacter
Azotobacter
Azotobacter is a genus of usually motile, oval or spherical bacteria that form thick-walled cysts and may produce large quantities of capsular slime. They are aerobic, free-living soil microbes which play an important role in the nitrogen cycle in nature, binding atmospheric nitrogen, which is...
. In this role vanadium replaces more common molybdenum
Molybdenum
Molybdenum , is a Group 6 chemical element with the symbol Mo and atomic number 42. The name is from Neo-Latin Molybdaenum, from Ancient Greek , meaning lead, itself proposed as a loanword from Anatolian Luvian and Lydian languages, since its ores were confused with lead ores...
or iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
, and gives the nitrogenase
Nitrogenase
Nitrogenases are enzymes used by some organisms to fix atmospheric nitrogen gas . It is the only known family of enzymes that accomplish this process. Dinitrogen is quite inert because of the strength of its N-N triple bond...
slightly different properties.
Fungi
Several species of macrofungi, namely Amanita muscariaAmanita muscaria
Amanita muscaria, commonly known as the fly agaric or fly amanita , is a poisonous and psychoactive basidiomycete fungus, one of many in the genus Amanita...
and related species, accumulate vanadium (up to 500 mg/kg in dry weight). Vanadium is present in the coordination complex, amavadin
Amavadin
Amavadin is a vanadium-containing anion found in three species of poisonous Amanita mushrooms: A. muscaria, A. regalis, and A. velatipes. Amavadin was first isolated and identified in 1972 by Kneifel and Bayer. This anion, which appears as a blue solution, is an eight-coordinate vanadium complex...
, in fungal fruit-bodies. However, the biological importance of the accumulation process is unknown. Toxin functions or peroxidase
Peroxidase
Peroxidases are a large family of enzymes that typically catalyze a reaction of the form:For many of these enzymes the optimal substrate is hydrogen peroxide, but others are more active with organic hydroperoxides such as lipid peroxides...
enzyme functions have been suggested.
Mammals and birds
RatRat
Rats are various medium-sized, long-tailed rodents of the superfamily Muroidea. "True rats" are members of the genus Rattus, the most important of which to humans are the black rat, Rattus rattus, and the brown rat, Rattus norvegicus...
s and chicken
Chicken
The chicken is a domesticated fowl, a subspecies of the Red Junglefowl. As one of the most common and widespread domestic animals, and with a population of more than 24 billion in 2003, there are more chickens in the world than any other species of bird...
s are also known to require vanadium in very small amounts and deficiencies result in reduced growth and impaired reproduction. Vanadium is a relatively controversial dietary supplement
Dietary supplement
A dietary supplement, also known as food supplement or nutritional supplement, is a preparation intended to supplement the diet and provide nutrients, such as vitamins, minerals, fiber, fatty acids, or amino acids, that may be missing or may not be consumed in sufficient quantities in a person's diet...
, primarily for increasing insulin
Insulin
Insulin is a hormone central to regulating carbohydrate and fat metabolism in the body. Insulin causes cells in the liver, muscle, and fat tissue to take up glucose from the blood, storing it as glycogen in the liver and muscle....
sensitivity and body-building. Whether it works for the latter purpose has not been proven, and there is some evidence that athletes who take it are merely experiencing a placebo effect
Placebo effect
Placebo effect may refer to:* Placebo effect, the tendency of any medication or treatment, even an inert or ineffective one, to exhibit results simply because the recipient believes that it will work...
. Vanadyl sulfate may improve glucose control in people with type 2 diabetes. In addition, decavanadate and oxovanadates are species that potentially have many biological activities and that have been successfully used as tools in the comprehension of several biochemical processes.
Safety
All vanadium compounds should be considered to be toxic. Tetravalent VOSO4 has been reported to be over 5 times more toxic than trivalent V2O3. The Occupational Safety and Health AdministrationOccupational Safety and Health Administration
The United States Occupational Safety and Health Administration is an agency of the United States Department of Labor. It was created by Congress of the United States under the Occupational Safety and Health Act, signed by President Richard M. Nixon, on December 29, 1970...
(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. The National Institute for Occupational Safety and Health
National Institute for Occupational Safety and Health
The National Institute for Occupational Safety and Health is the United States’ federal agency responsible for conducting research and making recommendations for the prevention of work-related injury and illness. NIOSH is part of the Centers for Disease Control and Prevention within the U.S...
(NIOSH) has recommended that 35 mg/m3 of vanadium be considered immediately dangerous to life and health. This is the exposure level of a chemical that is likely to cause permanent health problems or death.
Vanadium compounds are poorly absorbed through the gastrointestinal system. Inhalation exposures to vanadium and vanadium compounds result primarily in adverse effects on the respiratory system. 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, on liver, on neurological development in rats, and other organs.
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 male and female mice by inhalation in an NTP study, although the interpretation of the results has recently been disputed. Vanadium has not been classified as to carcinogenicity by the United States Environmental Protection Agency
United States Environmental Protection Agency
The U.S. Environmental Protection Agency is an agency of the federal government of the United States charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress...
.
Vanadium traces in diesel fuels present a corrosion hazard; it is the main fuel component influencing high temperature corrosion
High temperature corrosion
Hot corrosion is a mechanism of "high temperature corrosion", others include high temperature oxidation, sulfidation and carbonization.-Hot corrosion by sulfates:...
. During combustion, it oxidizes and reacts with sodium and sulfur, yielding vanadate
Vanadate
In chemistry, a vanadate is a compound containing an oxoanion of vanadium generally in its highest oxidation state of +5. The simplest vanadate ion is the tetrahedral, orthovanadate, VO43− anion, which is present in e.g. sodium orthovanadate and in solutions of V2O5 in strong base...
compounds with melting points down to 530 °C, which attack the passivation layer on steel, rendering it susceptible to corrosion. The solid vanadium compounds also cause abrasion of engine components.
External links
- National Instrument Vanadium Technical Report Vanadium recovery methods
- ATSDR – ToxFAQs: Vanadium