Vanadium is a soft and ductile, silver-grey metal. It has good resistance to
corrosion by alkalis, sulfuric and hydrochloric acid. It oxidizes readily at
about 933 K (660 C). Vanadium has good structural strength and a low fission
neutron cross section, making it useful in nuclear applications. Although a
metal, it shares with chromium and manganese the property of having valency
oxides with 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 rarely seen.
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
- Vanadium steel alloys are used in axles, crankshafts, gears, and other
- It is an important carbide stabilizer in making steels.
- Because of its low fission neutron cross section, vanadium has nuclear
- 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
- Added to corundum to make simulated alexandrite jewelry.
- Vanadate electrochemical conversion coatings for protecting steel against
rust and corrosion
- Used to make lacrosse shafts
- Possibly used to make Wootz steel and Damascus steel.
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.
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
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
Various oxidation states of vanadium
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.
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
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.
Powdered metallic vanadium is a fire hazard, and unless known otherwise, all
vanadium compounds should be considered highly toxic. Generally, the higher the
oxidation state of vanadium, the more toxic the compound is. The most dangerous
compound is vanadium pentoxide.
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