- Vanadium (V) is a hard, silvery-gray transition metal with atomic number 23, positioned in Group 5 of the periodic table.
- It has five valence electrons—two in the 4s subshell and three in the 3d subshell—and exhibits a wide range of oxidation states from −1 to +5, with +5, +4, and +3 being the most common in its compounds. Its atomic structure consists of twenty-three protons, typically twenty-eight neutrons, and twenty-three electrons arranged in four shells.
- Naturally occurring vanadium consists of two isotopes: the stable vanadium-51 (⁵¹V), making up about 99.75% of natural vanadium, and the radioactive vanadium-50 (⁵⁰V), which has an extremely long half-life of approximately 1.4 × 10¹⁷ years.
- Vanadium occurs naturally in about 65 different minerals, as well as in fossil fuels such as crude oil and coal. Important vanadium-bearing minerals include vanadinite (Pb₅(VO₄)₃Cl), patronite (VS₄), carnotite (K₂(UO₂)₂(VO₄)₂·3H₂O), and roscoelite (a vanadium-rich mica). The majority of vanadium is obtained from magnetite ores containing vanadium, primarily mined in South Africa, China, and Russia. It is also recovered from petroleum residues and fly ash from oil-burning power plants.
- The element was first discovered in 1801 by Spanish mineralogist Andrés Manuel del Río, who found it in a Mexican lead ore and named it “erythronium” due to the red color of its salts. However, his discovery was dismissed at the time. In 1830, Swedish chemist Nils Gabriel Sefström rediscovered the element and named it “vanadium” after Vanadis, a Norse goddess associated with beauty, in reference to the vivid colors of its various compounds.
- Vanadium’s primary industrial use is in the production of strong, corrosion-resistant alloys. Adding as little as 0.1–0.2% vanadium to steel significantly increases its strength, toughness, and wear resistance, producing high-strength low-alloy (HSLA) steels used in tools, pipelines, buildings, and automotive components. Titanium–vanadium–aluminum alloys are widely used in aerospace applications, including jet engines and airframes, due to their high strength-to-weight ratio.
- In the chemical industry, vanadium(V) oxide (V₂O₅) is used as a catalyst in the contact process for producing sulfuric acid and in the manufacture of certain polymers. Vanadium compounds also play a role in energy storage—particularly in vanadium redox flow batteries (VRFBs), which are promising for large-scale renewable energy storage due to their long cycle life and ability to store energy for extended periods.
- Chemically, vanadium is notable for its colorful coordination compounds, which can display vivid hues depending on oxidation state: +5 (yellow), +4 (blue), +3 (green), and +2 (violet). It resists corrosion by forming a stable oxide film, though it reacts readily with strong acids and bases.
- Biologically, vanadium is present in trace amounts in many organisms and may play a minor role in certain biological processes, such as enzyme activation in some marine life. In humans, it is not considered essential, though extremely small amounts are found in tissues. Some vanadium compounds have been studied for potential therapeutic effects, including in blood sugar regulation, but their toxicity at higher doses limits use.
- Environmentally, vanadium emissions from burning fossil fuels can contribute to air pollution, and exposure to high concentrations of vanadium dust or compounds can cause respiratory and other health issues. However, in stable alloy or oxide forms, vanadium poses minimal environmental hazards.
