|Name, Symbol, Number||Vanadium, V, 23|
|Chemical series||Transition metals|
|Group, Period, Block||5 , 4 , d|
|Density, Hardness||6110 kg/m3, 7.0|
|Appearance||silvery grey metallic|
|Atomic weight||50.9415 amu|
|Atomic radius (calc.)||135 (171) pm|
|Covalent radius||125 pm|
|van der Waals radius||n/a pm|
|e- 's per energy level||2, 8, 11, 2|
|Oxidation states (Oxide)||5,3 (amphoteric)|
|Crystal structure||body centered cubic|
|State of matter||solid (__)|
|Melting point||2175 K (3456 °F)|
|Boiling point||3682 K (6168 °F)|
|Molar volume||8.32 ×1010-3 m3/mol|
|Heat of vaporization||0.452 kJ/mol|
|Heat of fusion||20.9 kJ/mol|
|Vapor pressure||3.06 Pa at 2175 K|
|Velocity of sound||4560 m/s at 293.15 K|
|Electronegativity||1.63 (Pauling scale)|
|Specific heat capacity||490 J/(kg·K)|
|Electrical conductivity||4.89 106/m ohm|
|Thermal conductivity||30.7 W/(m·K)|
|1st ionization potential||650.9 kJ/mol|
|2nd ionization potential||1414 kJ/mol|
|3rd ionization potential||2830 kJ/mol|
|4th ionization potential||4507 kJ/mol|
|5th ionization potential||6298.7 kJ/mol|
|Most Stable Isotopes|
|SI units & STP are used except where noted.|
|Table of contents|
4 Biological Role
9 External Links
Vanadium is a soft and ductile, bright white metal. It has good resistance to corrosion by alkalis, sulphuric and hydrochloric acid. It oxidizes readily at about 933 K. Vanadium has good structural strength and a low fission neutron cross section, making it useful in nuclear applications. It is intermediate between the metals and the non-metals, having both basic and acid properties.
Common oxidation states of vanadium include +2, +3, +4 and +5. A popular experiment with ammonium vanadate (NH4VO3), reducing the compound with zinc metal, can demonstrate colorimetrically all four of these vanadium oxidation states. A +1 oxidation state is also rarely seen.
Approximately 80% of vanadium produced is used as ferrovanadium or as a steel additive. Other uses;
- In such alloys as:
- Vanadium steel alloys are used in axles, crankshafts, gears, and other critical components.
- It is an important carbide stabilizer in making steels.
- Because of its low fission neutron cross section, vanadium has nuclear applications.
- Vanadium foil is used in cladding titanium to steel.
- Vanadium-gallium tape is in superconducting magnets (175,000 gauss).
- Vanadium compounds are used as catalysts in producing maleic anhydride and sulfuric acid.
- Vanadium pentoxide (V2O5) is used in ceramics and as a catalyst.
HistoryVanadium (Scandinavian goddess, Vanadis) was originally discovered by Andres Manuel del Rio (a Spanish mineralogist) at Mexico City in 1801, who called it "brown lead" (now named vanadinite). Through experimentation, he saw that the colors it exhibited were reminiscent of chromium, so he named the element panchromium. He later renamed this compound erythronium, since most of the salts turned red when heated. A French chemist incorrectly declared that del Rio's new element was only impure chromium. Del Rio thought himself to be mistaken and accepted the statement of the French chemist.
Metallic vanadium was isolated by Henry Enfield Roscoe in 1867, who reduced the vanadium chloride (VCl3) with hydrogen. The name vanadium comes from Vanadis, the goddess of beauty in Scandinavian mythology because the element has beautiful multicolored chemical compounds.
In biology, a vanadium atom is an essential component of some enzymes, particularly the vanadium nitrogenase used by some nitrogen-fixing microorganisms. Vanadium is essential to ascidians, or sea squirts. The concentration of vanadium in their bodies is one million times higher than the concentration of vanadium in the water around them. Rats and chickens are also known to require vanadium in very small amounts and deficiencies result in reduced growth and impaired reproduction.
Administration of oxovanadium compounds has been shown to alleviate diabetes mellitus symptoms in certain animal models and humans. Much like the chromium effect on sugar metabolism, the mechanism of this effect is unknown.
Vanadium is never found unbound in nature but it does occur in about 65 different minerals among which are patronite (VS4), vanadinite ]Pb5(VO4)3Cl, and carnotite K2(UOO2)2(VO4)2.3H2O. Vanadium is also present in bauxite, and in carbon containing deposits such as crude oil, coal, oil shale and tar sands. The spectra of vanadium has also been detected in light from the sun and some other stars.
Much of the vanadium metal being produced is now made by calcium reduction of V2O5 in a pressure vessel. Vanadium is usually recovered as a by-product or co-product, and so world resources of the element are not really indicative of available supply.
Vanadium pentoxide (V2O5) is used as a catalyst, dye and color-fixer.
Naturally occurring vanadium is composed of 1 stable isotope; V-51. 15 radioisotopes have been characterized with the most stable being V-50 with a half-life of 1.4E17 years, V-49 with a half-life of 330 days, and V-48 with a half-life of 15.9735 days. All of the remaining radioactive isotopes have half-lifes that are less than 1 hour and the majority of these have half lifes that are less than 10 seconds. This element also has 1 meta state.
The isotopes of vanadium range in atomic weight from 43.981 amu (V-43) to 59.959 amu (V-59). The primary decay mode before the most abundant stable isotope, V-51, is electron capture and the primary mode after is beta decay. The primary decay products before V-51 are element 22 (titanium) isotopes and the primary products after are element 24 (chromium) isotopes.
Powdered metallic vanadium is a fire hazard, and vanadium compounds should be considered highly toxic. Vanadium compounds may cause lung cancer if inhaled.
The Occupational Safety and Health Administration (OSHA) has set an exposure limit of 0.05 mg/m3 for vanadium pentoxide dust and 0.1 mg/m3 for vanadium pentoxide fumes in workplace air for an 8-hour workday, 40-hour work week.
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.