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Vanadium
Gist
Vanadium is a chemical element, symbolized as V with an atomic number of 23. It's a hard, silvery-grey, malleable transition metal. While not typically found in its pure form in nature, it's widely used in alloys, particularly steel, to enhance strength and durability. Vanadium also plays a role in various industrial and potentially biological applications, including catalysis, batteries, and even some medicinal uses.
Summary
Vanadium is a chemical element; it has symbol V and atomic number 23. It is a hard, silvery-grey, malleable transition metal. The elemental metal is rarely found in nature, but once isolated artificially, the formation of an oxide layer (passivation) somewhat stabilizes the free metal against further oxidation.
Spanish-Mexican scientist Andrés Manuel del Río discovered compounds of vanadium in 1801 by analyzing a new lead-bearing mineral he called "brown lead". Though he initially presumed its qualities were due to the presence of a new element, he was later erroneously convinced by French chemist Hippolyte Victor Collet-Descotils that the element was just chromium. Then in 1830, Nils Gabriel Sefström generated chlorides of vanadium, thus proving there was a new element, and named it "vanadium" after the Scandinavian goddess of beauty and fertility, Vanadís (Freyja). The name was based on the wide range of colors found in vanadium compounds. Del Río's lead mineral was ultimately named vanadinite for its vanadium content. In 1867, Henry Enfield Roscoe obtained the pure element.
Vanadium occurs naturally in about 65 minerals and fossil fuel deposits. It is produced in China and Russia from steel smelter slag. Other countries produce it either from magnetite directly, flue dust of heavy oil, or as a byproduct of uranium mining. It is mainly used to produce specialty steel alloys such as high-speed tool steels, and some aluminium alloys. The most important industrial vanadium compound, vanadium pentoxide, is used as a catalyst for the production of sulfuric acid. The vanadium redox battery for energy storage may be an important application in the future.
Large amounts of vanadium ions are found in a few organisms, possibly as a toxin. The oxide and some other salts of vanadium have moderate toxicity. Particularly in the ocean, vanadium is used by some life forms as an active center of enzymes, such as the vanadium bromoperoxidase of some ocean algae.
Details
Vanadium (V) is a chemical element, silvery white soft metal of Group 5 (Vb) of the periodic table. It is alloyed with steel and iron for high-speed tool steel, high-strength low-alloy steel, and wear-resistant cast iron.
Vanadium was discovered (1801) by the Spanish mineralogist Andrés Manuel del Río, who named it erythronium but eventually came to believe it was merely impure chromium. The element was rediscovered (1830) by the Swedish chemist Nils Gabriel Sefström, who named it after Vanadis, the Scandinavian goddess of beauty and youth, a name suggested by the beautiful colours of vanadium’s compounds in solution. The English chemist Henry Enfield Roscoe first isolated the metal in 1867 by hydrogen reduction of vanadium dichloride, VCl2, and the American chemists John Wesley Marden and Malcolm N. Rich obtained it 99.7 percent pure in 1925 by reduction of vanadium pentoxide, V2O5, with calcium metal.
Found combined in various minerals, coal, and petroleum, vanadium is the 22nd most abundant element in Earth’s crust. Some commercial sources are the minerals carnotite, vanadinite, and roscoelite. (Deposits of the important vanadium-bearing mineral patronite occurring in coal at Mina Ragra, Peru, have been materially depleted.) Other commercial sources are vanadium-bearing magnetite and flue dust from smokestacks and boilers of ships burning certain Venezuelan and Mexican oils. China, South Africa, and Russia were the leading producers of vanadium in the early 21st century.
Vanadium is obtained from ores as vanadium pentoxide (V2O5) through a variety of smelting, leaching, and roasting processes. The pentoxide is then reduced to ferrovanadium or vanadium powder. The preparation of very pure vanadium is difficult because the metal is quite reactive toward oxygen, nitrogen, and carbon at elevated temperatures.
Vanadium metal, sheet, strip, foil, bar, wire, and tubing have found use in high-temperature service, in the chemical industry, and in bonding other metals. Because the major commercial use of vanadium is in steel and cast iron, to which it lends ductility and shock resistance, most of the vanadium produced is used with iron as ferrovanadium (about 85 percent vanadium) in making vanadium steels. Vanadium (added in amounts between 0.1 and 5.0 percent) has two effects upon steel: it refines the grain of the steel matrix, and with the carbon present it forms carbides. Thus, vanadium steel is especially strong and hard, with improved resistance to shock. When the very pure metal is required, it may be obtained by processes similar to those for titanium. Very pure vanadium metal resembles titanium in being quite corrosion resistant, hard, and steel gray in color.
Vanadium compounds (pentoxide and certain vanadates) are used as catalysts in the contact process for manufacturing sulfuric acid; as oxidation catalysts in the syntheses of phthalic and maleic anhydrides; in the manufacture of polyamides such as nylon; and in the oxidation of such organic substances as ethanol to acetaldehyde, sugar to oxalic acid, and anthracene to anthraquinone.
Natural vanadium consists of two isotopes: stable vanadium-51 (99.76 percent) and weakly radioactive vanadium-50 (0.24 percent). Nine artificial radioactive isotopes have been produced. Vanadium dissolves in concentrated sulfuric acid, nitric acid, hydrofluoric acid, and aqua regia. In the massive state it is not attacked by air, water, alkalies, or nonoxidizing acids other than hydrofluoric acid. It does not tarnish in air readily but when heated combines with nearly all nonmetals. For vanadium the important oxidation states are +2, +3, +4, and +5. The oxides corresponding to the four oxidation states are VO, V2O3, VO2, and V2O5. The hydrogen-oxygen compounds of vanadium in the two lower oxidation states are basic; in the two higher, amphoteric (both acidic and basic). In aqueous solution the ions exhibit different colours depending on the oxidation state—lavender in the +2 state, green in the +3 state, blue in the +4 state, and yellow in the +5 state.
Element Properties
atomic number : 23
atomic weight : 50.942
melting point : 1,890 °C (3,434 °F)
boiling point : 3,380 °C (6,116 °F)
specific gravity : 5.96 at 20 °C (68 °F)
oxidation states : +2, +3, +4, +5.
Additional Information:
Appearance
A silvery metal that resists corrosion.
Uses
About 80% of the vanadium produced is used as a steel additive. Vanadium-steel alloys are very tough and are used for armour plate, axles, tools, piston rods and crankshafts. Less than 1% of vanadium, and as little chromium, makes steel shock resistant and vibration resistant. Vanadium alloys are used in nuclear reactors because of vanadium’s low neutron-absorbing properties.
Vanadium(V) oxide is used as a pigment for ceramics and glass, as a catalyst and in producing superconducting magnets.
Biological role
Vanadium is essential to some species, including humans, although we need very little. We take in just 0.01 milligrams each day, and this is more than sufficient for our needs. In some compounds vanadium can become toxic.
Natural abundance
Vanadium is found in about 65 different minerals including vanadinite, carnotite and patronite. It is also found in phosphate rock, certain iron ores and some crude oils in the form of organic complexes.
Vanadium metal is obtained by reducing vanadium(V) oxide with calcium in a pressure vessel. Vanadium of high purity can be obtained by reducing vanadium(III) chloride with magnesium.
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