vanádium

Vanadium is a chemical element with the symbol V and atomic number 23. It is a hard, silvery-gray transition metal that occurs in several oxidation states, most commonly +2, +3, +4, and +5. Vanadium has a high melting point of about 1910°C, a density near 6.0 g/cm3, and crystallizes in a body-centered cubic structure. It forms a range of oxides and complex compounds, many with vivid colors, and it is valued for its ability to stabilize serious metallurgical structures.

Natural vanadium consists mainly of the isotopes V-51 and V-50, with V-51 accounting for the vast majority of natural vanadium; several radioisotopes have been observed in trace amounts or synthetic contexts. Vanadium is relatively abundant in the Earth's crust and is typically obtained as a by-product of mining other metals or from vanadium-rich ore deposits such as vanadinite, carnotite, and magnetite-bearing rocks. Major producers in the modern era include China, Russia, South Africa, and Kazakhstan, with China often responsible for the largest portion of production.

The principal use of vanadium is as an alloying element in steel and other metals; small additions improve strength, hardness, and resistance to fatigue and creep, making vanadium common in tools, high-strength steels, and aerospace alloys. It is also used as a catalyst, particularly in sulfuric acid production, and in some chemical processes. In energy storage, vanadium redox flow batteries are being developed for grid-scale applications.

Historically, vanadium was first identified in 1801 by Andrés Manuel del Río in Mexico, who named it vanadium; its existence was independently confirmed by Nils Gabriel Sefström in 1830, who adopted the present name after Vanadis, a Norse goddess. Some vanadium compounds are toxic, so industrial handling requires appropriate safety measures.