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vanadium 音標拼音: [vən'ediəm] n. 釩 釩 vanadium n 1: a soft silvery white toxic metallic element used in steel alloys; it occurs in several complex minerals including carnotite and vanadinite [ synonym: { vanadium}, { V}, { atomic number 23}] Vanadium \ Va* na" di* um\, n. [ NL., fr. Icel. Vanad[ imac] 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 metallic powder. It is intermediate between the metals and the non- metals, having both basic and acid properties. Symbol V ( or Vd, rarely). Atomic weight 50. 94 ( C12= 12. 000). [ 1913 Webster PJC] vanadiumSymbol: VAtomic number: 23Atomic weight: 50. 9415Soft and ductile, bright white metal. Good resistance to corrosion byalkalis, sulphuric and hydrochloric acid. It oxidizes readily about933K. There are two naturally occurring isotopes of vanadium, and 5radioisotopes, V- 49 having the longest half- life at 337 days. Vanadiumhas nuclear applications, the foil is used in cladding titanium tosteel, and vanadium- gallium tape is used to produce a superconductive magnet. Originally discovered by Andres Manuel del Rio of Mexico City in 1801. His discovery went unheeded, however, and in 1820, Nils Gabriel Sefstronof Sweden rediscovered it. Metallic vanadium was isolated by HenryEnfieldRoscoe in 1867. The name vanadium comes from { Vanadis}, a goddess ofScandinavian mythology. Silvery- white metallic transition element. Vanadium is essential to { ascidian} s. Rats and chickens are also knownto require it. Metal powder is a fire hazard, and vanadium compoundsshould be considered highly toxic. May cause lung cancer if inhaled.
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