vanadium


vanadium
/veuh nay"dee euhm/, n. Chem.
a rare element occurring in certain minerals and obtained as a light-gray powder with a silvery luster or as a ductile metal: used as an ingredient of steel to toughen it and increase its shock resistance. Symbol: V; at. wt.: 50.942; at. no.: 23; sp. gr.: 5.96.
[ < NL (1830) < Icel Vanad(ís) epithet of Freya (Vana, gen. of Vanir VANIR + dís goddess) + NL -ium -IUM]

* * *

Metallic chemical element, one of the transition elements, chemical symbol V, atomic number 23.

A silvery white, soft metal found (always combined) in various minerals, coal, and petroleum, it is used in alloys with steel and iron for high-speed tool steel, high-strength low-alloy steel, and wear-resistant cast iron. Unalloyed, it is used in high-temperature applications, as a target in X-ray applications, and as a catalyst. Its compounds, in which it has various valences, have many beautiful colours in solution and are used as catalysts and mordants (see dye).

* * *

 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 the 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.

      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 (steel). 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 colour.

      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.

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 (20° C)
oxidation states
+2, +3, +4, +5
electronic config.
[Ar]3d34s2

* * *


Universalium. 2010.

Look at other dictionaries:

  • Vanadium — (IPAEng|vəˈneɪdiəm) is a chemical element that has the symbol V and atomic number 23. A soft and ductile element, vanadium naturally occurs in about 65 different minerals and is used mainly to produce certain alloys. It is one of the 596 elements …   Wikipedia

  • VANADIUM — Le vanadium est l’élément chimique de symbole V et de numéro atomique 23. C’est un élément de transition du groupe Va de la classification périodique. Il a été découvert de façon certaine en 1830, dans un minerai de fer suédois, par Nils Gabriel… …   Encyclopédie Universelle

  • Vanadium — Titane ← Vanadium → Chrome …   Wikipédia en Français

  • vanadium — Symbol: V Atomic number: 23 Atomic weight: 50.9415 Soft and ductile, bright white metal. Good resistance to corrosion by alkalis, sulphuric and hydrochloric acid. It oxidizes readily about 933K. There are two naturally occurring isotopes of… …   Elements of periodic system

  • Vanadium — Va*na di*um, n. [NL., fr. Icel. Vanad[=i]s, a surname of the Scandinavian goddess Freya.] (Chem.) A rare element of the nitrogen phosphorus group, found combined, in vanadates, in certain minerals, and reduced as an infusible, grayish white… …   The Collaborative International Dictionary of English

  • Vanadium [1] — Vanadium (Vanadin) V, Atomgew. 51,2, ein hellgraues, silberglänzendes Pulver, dessen spez. Gew. 5,5 und dessen Schmelzpunkt 1680° ist. Es verhält sich in chemischer Beziehung ähnlich wie Niob und Tantal; oxydiert sich langsam an der Luft,… …   Lexikon der gesamten Technik

  • Vanadium [2] — Vanadium (Vanadin), V, Atomgew. 51,0, spez. Gew. 5,7, Schmelzpunkt 1715°. Vanadinit ist in Peru und Neu Mexiko abbauwürdig [1]. Die wichtigsten seiner fünf Oxyde sind: Vanadiummonoxyd V2O, Vanadiumtrioxyd V2O3 und Vanadiumpentoxyd… …   Lexikon der gesamten Technik

  • vanadium — rare metallic element, 1833, named 1830 by Swedish chemist Nils Gabriel Sefström (1787 1845), from O.N. Vanadis, one of the names of the Norse beauty goddess Freyja (see FREYA (Cf. Freya)), perhaps because of its colorful compounds …   Etymology dictionary

  • vanadium — [və nā′dē əm] n. [ModL < ON Vanadis,FREYA + IUM: name proposed (1831) by BERZELIUS Baron Jöns Jakob for element discovered independently by N. G. Sefström (1787 1845), Swed chemist, and previously (1801) by A. M. del Rio (1764 1849), Mex… …   English World dictionary

  • Vanadium — Eigenschaften …   Deutsch Wikipedia


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.