Vanadium




Vanadium

MELTING POINT: 1,910 ±10°C
BOILING POINT: 3,047°C
DENSITY: 6.11 g/cm 3
MOST COMMON IONS: V 2+ , V 3+ , VO + , VO 2 +

Vanadium is a soft silver metal in group 5B of the Periodic Table. It was discovered in Mexican lead ore by Andreas Manuel del Rio in 1801. Because of the red color of its salts, he named it erythronium (the Greek word erythro means "red"). Upon challenge by H. V. Colett-Desotils, del Rio withdrew his claim. In 1830 the element was rediscovered by Nils Selfstöm in iron ore. Since the element is found in compounds of many different colors, he named it "vanadium" after the Scandinavian goddess of beauty, Vanadis.

Vanadium is the nineteenth element in abundance (136 ppm) and the fifth most abundant transition element in Earth's crust. It is found in approximately sixty-five different minerals (such as roscoelite and vanadinite), phosphate rock, iron ores, and some crude oils as organic complexes. Since there are few concentrated deposits of vanadium compounds, it is obtained as a coproduct of refining. The element has two naturally occurring isotopes : 50 V (0.25%) and 51 V (99.75%).

Although vanadium is an essential trace element , its exact role has not been determined. It is found in the blood of the ascidian seaworm. A related species has vanadium concentrations of up to 1.45 percent in its blood cells. The metal may play a role in the oxygen transport system.

Vanadium reacts with most nonmetals at high reaction temperatures (660°C; 1,220°F). The compounds of vanadium reflect the varied oxidation states possible for this element. Formal oxidation states of +5 to −1 have been found, with the +4 state being the most stable. The element has good corrosion resistance to alkali, acid, and salt water. For this reason it is used in rust resistant springs and high speed tools. Approximately 80 percent of the vanadium produced yearly is used as an additive to produce steel that has a resistance to wear. Vanadium oxide is used in ceramics and as a catalyst .

SEE ALSO Corrosion ; Steel .

Catherine H. Banks

Bibliography

Greenwood, N. N., and Earnshaw, A. (1997). Chemistry of the Elements, 2nd edition. Boston: Butterworth-Heinemann.

Lide, David R., ed. (2003). "Vanadium." In The CRC Handbook of Chemistry and Physics, 84th edition. Boca Raton, FL: CRC Press.

Internet Resources

"Vanadium." U.S. Geological Survey, Mineral Commodity Summaries. Available from http://minerals.usgs.gov/minerals/pubs/commodity/vanadium/700303.pdf .



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