Element #23

Approximately 80% of vanadium produced is used as ferrovanadium or as a steel additive. Other uses:

• In such alloys as
  • specialty stainless steel, e.g. for use in surgical instruments and tools.
  • rust resistant and high speed tool steels.
  • mixed with aluminium in titanium alloys used in jet engines and high-speed airframes
• 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 used in superconducting magnets (175,000 gauss).
• Vanadium pentoxide V₂O₅ is used as a catalyst in manufacturing sulfuric acid (via the contact process) and maleic anhydride. It is also used in making ceramics.
• Glass coated with vanadium dioxide VO₂ can block infrared radiation (and not visible light) at a specific temperature.
• Electrical fuel cells and storage batteries such as vanadium redox batteries.
• Added to corundum to make simulated alexandrite jewelry.
• Vanadate electrochemical conversion coatings for protecting steel against rust and corrosion
• Used to make lacrosse shafts

Hisory

Vanadium was originally discovered by Andrés Manuel del Río (a Spanish-born Mexican mineralogist) in Mexico City, in 1801. He called it "brown lead" (now named vanadinite). Through experimentation, its colors reminded him of chromium, so he named the element panchromium. He later renamed this compound erythronium, since most of the salts turned red when heated. The French chemist Hippolyte Victor Collet-Descotils incorrectly declared that del Río's new element was only impure chromium. Del Río thought himself to be mistaken and accepted the statement of the French chemist that was also backed by del Río's friend Baron Alexander von Humboldt.

In 1831, Sefström of Sweden rediscovered vanadium in a new oxide he found while working with some iron ores and later that same year Friedrich Wöhler confirmed del Río's earlier work. Later, George William Featherstonhaugh, one of the first US geologists, suggested that the element should be named "rionium" after del Río, but this never happened.

Metallic vanadium was isolated by Henry Enfield Roscoe in 1867, who reduced vanadium(III) chloride VCl₃ with hydrogen. The name vanadium comes from Vanadis, a goddess in Scandinavian mythology, because the element has beautiful multicolored chemical compounds.

Compounds

Vanadium pentoxide V₂O₅ is used as a catalyst principally in the production of sulfuric acid. It is the source of vanadium used in the manufacture of ferrovanadium. It can be used as a dye and color-fixer.

Vanadyl sulfate VOSO₄, also called vanadium(IV) sulfate oxide hydrate, is used as a relatively controversial dietary supplement, primarily for increasing insulin sensitivity and body-building. Whether it works for the latter purpose has not been proven, and there is some evidence that athletes who take it are merely experiencing a placebo effect.

Vanadium(IV) chloride VCl₄ is a soluble form of vanadium that is commonly used in the laboratory. V(IV) is the reduced form of V(V), and commonly occurs after anaerobic respiration by dissimilatory metal reducing bacteria. VCl₄ reacts violently with water.

Toxicity of vanadium compounds

The toxicity of vanadium depends on its physico-chemical state; particularly on its valence state and solubility. Tetravalent VOSO₄ has been reported to be more than 5 times as toxic as trivalent V₂O₃ (Roschin, 1967). Vanadium compounds are poorly absorbed through the gastrointestinal system. Inhalation exposures to vanadium and vanadium compounds result primarily in adverse effects to the respiratory system (Sax, 1984; ATSDR, 1990; Ress et al., 2003; Worle-Knirsch et al., 2007). Quantitative data are, however, insufficient to derive a subchronic or chronic inhalation reference dose. Other effects have been reported on blood parameters after oral or inhalation exposures (Scibior et al., 2006; Gonzalez-Villalva et al., 2006), on liver (Kobayashi et al., 2006), neurological development in rats (Soaso and Garcia, 2007), and other organs.

There is little evidence that vanadium or vanadium compounds are reproductive toxins or teratogens. Vanadium pentoxide was reported to be carcinogenic in male rats and male and female mice by inhalation in an NTP study (Ress et al., 2003), although the interpretation of the results has recently been disputed (Duffus, 2007). Vanadium has not been classified as to carcinogenicity by the U.S. EPA (1991a).

Various oxidation states of vanadium ions

It is known that vanadium gets the oxidation states +2, +3, +4, +5. To observe the colours of these states, ammonium metavanadate (NH₄VO₃) can be used as a starting agent. It must be acidified beforehand so dioxovanadium(V) ion, VO₂⁺ (yellow +5 oxidation number) is produced. In alkaline medium, the stable form of vanadium(V) state is VO₃^-.

Adding zinc powder and concentrated hydrochloric acid continuously, VO₂⁺ is reduced into blue VO²⁺.

It can be seen that during the reaction, the mixture is green in colour as the original yellow of the +5 state and the blue of the +4 are present.

Continuously adding Zn powder and concentrated HCl, blue VO²⁺ is reduced to green V³⁺. V³⁺ is then reduced to violet V²⁺ by Zn powder and concentrated HCl again.

Isotopes

Naturally occurring vanadium is composed of one stable isotope ⁵¹V and one radioactive isotope ⁵⁰V with a half-life of 1.5×10¹⁷ years. 24 artificial radioisotopes have been characterized (in the range of mass number between 40 and 65) with the most stable being ⁴⁹V with a half-life of 330 days, and ⁴⁸V with a half-life of 15.9735 days. All of the remaining radioactive isotopes have half-lives shorter than an hour, the majority of them below 10 seconds. In 4 isotopes, metastable excited states were found (including 2 metastable states for ⁶⁰V).

The primary decay mode before the most abundant stable isotope ⁵¹V is electron capture. The next most common mode is beta decay. The primary decay products before ⁵¹V are element 22 (titanium) isotopes and the primary products after are element 24 (chromium) isotopes.