Vanadium

Description

Named after the Scandinavian goddess of youth and beauty, vanadium is a trace element that has gained attention in recent years as a possible aid in controlling diabetes. While such macrominerals as calcium, magnesium , and potassium have become household names because they make up over 98% of the body's mineral content, certain trace minerals are also considered essential in very tiny amounts to maintain health and ensure proper functioning of the body. They usually act as coenzymes, working as a team with proteins to facilitate important chemical reactions. Even without taking vanadium supplements, people have about 20–25 micrograms (mcg) of the mineral in their bodies, which is derived from an average balanced diet. Despite the fact that vanadium has been studied for over 40 years, it is still not known for certain if the mineral is critical for optimal health. Whether taking extra amounts of vanadium is therapeutic or harmful is even more controversial. Like chromium , another trace mineral, vanadium has become the focus of study as a possible aid in lowering blood sugar levels in people with diabetes. Vanadium has also been touted as a potential treatment for osteoporosis . Some athletes and weight lifters take it to build muscle or improve performance.

Studies in animals suggest that vanadium may be necessary for the formation of bones, teeth, and cartilage. The mineral may also play a role in growth and reproduction as well as affect the processing of cholesterol and insulin in the body. In one animal study, goat kids whose mothers received a diet deficient in vanadium showed skeletal damage; they died within days of their birth. In studies of mice, vanadium has been shown to lower blood sugar and levels of low-density lipoprotein (LDL) cholesterol and triglyceride. It is not certain, however, that such study results as these confirm the nutritional importance of the mineral for human beings. The effects of a vanadium-free diet have not been studied in people. Even if vanadium supplements prove to be effective for certain purposes, such as helping to control diabetes, animal studies suggest that the high dosages of vanadium necessary to produce results may be harmful. High dosages are often necessary because vanadium is not well absorbed by the body. As of 2000, a significant amount of research is still required to determine if vanadium can in fact produce significant health benefits safely and effectively. The proper dosage of the mineral supplement has also yet to be determined.

General Use

Vanadium has been investigated most often as a possible aid in controlling diabetes. Studies in animals with type 1 (insulin-dependent) and type 2 (non-insulin-dependent) diabetes indicate that vanadium can help to improve blood sugar levels. Studies using human subjects have produced encouraging if preliminary results. Vanadium is used by some athletes and weight lifters to build muscle despite the fact that it does not appear to be effective for this purpose. Moreover, the potential usefulness of vanadium in treating osteoporosis is considered highly speculative. All of the human studies discussed below were conducted in small numbers of people for short periods of time and involved relatively high dosages of the mineral.

Diabetes

Several studies conducted in people suggest that vanadium may help to control blood sugar levels in diabetics. The mineral appears to work by mimicking the effects of insulin or by increasing the body's sensitivity to the hormone. This mechanism could allow diabetics to effectively control their blood sugar while using lower dosages of insulin medication. In a placebo-controlled study published in 1996 in the medical journal Metabolism, eight people with type 2 diabetes received vanadium for one month. Researchers found that vanadium was moderately successful in lowering blood sugar levels and had few side effects. Six of the eight patients taking vanadium during the study experienced gastrointestinal side effects during the first week of treatment, but these disappeared with continued use. In another small study of vanadium involving people with type 2 diabetes, published in the Journal of Clinical Investigation in 1995, researchers from the Albert Einstein College of Medicine reported that three weeks of treatment with the mineral improved the body's sensitivity to insulin. The effects of vanadium in lowering blood sugar levels persisted for up to two weeks after the drug was discontinued. A study published in the journal Diabetes in 1996, which involved seven people with type 2 diabetes as well as six nondiabetics, reported that vanadium improved insulin sensitivity in the diabetic subjects. Interestingly, the mineral did not improve sensitivity in the subjects who did not have the disease.

Sports medicine

The use of vanadium by body builders appears to stem from a misunderstanding of the mineral's effects. Because insulin is a hormone that plays a role in increasing muscle mass, some weight lifters have taken vanadium in high dosages because they believe it will act like insulin and make them stronger. The problem is that vanadium does not appear to mimic insulin or increase its efficiency in healthy people, only in diabetics. For people considering vanadium as an aid in strengthening muscles, the scientific evidence is not very convincing. In one double-blind, placebo-controlled study published in the International Journal of Sport Nutrition in 1996, high dosages of vanadium were given to a few dozen weight trainers for 12 weeks. The bench press and leg extension weight-training exercises were used to measure results. Researchers found that there was no difference in body composition between those who took vanadium and those in the placebo group. Vanadium appeared to slightly enhance performance during the leg extension aspect of the study, but this advantage can be explained by other factors and cannot be attributed to the mineral itself with any certainty.

Osteoporosis

It is important not to confuse vanadium with calcium . Calcium is considered an essential building block of bone, and calcium supplements are often an important part of a bone-strengthening program in women with osteoporosis. Studies in mice indicating that vanadium is also deposited in bone have led to suggestions that the mineral may be effective as a potential treatment for osteoporosis. It is known, however, that minerals can be added to bones without actually making them stronger. There is no evidence that taking vanadium supplements can increase bone density in humans.

Preparations

The estimated dosage of vanadium, which is available as an over-the-counter dietary supplement, generally ranges from 10–30 mcg a day. It is important to remember, however, that safe and effective dosages for the mineral have not yet been established. Some practitioners of complementary medicine, such as Dr. Robert Atkins, have recommended dosages as high as 25–50 mg (milligrams, not micrograms) daily for people with diabetes. The long-term health risks associated with taking dosages in this range are unknown.

Even without taking supplements, most adults get anywhere between 10–60 mcg of vanadium through a normal diet. Some authorities believe it is safer for people to avoid vanadium supplements altogether and increase their intake of foods known to contain the mineral. These include meat, seafood, whole grains, vegetable oil, canned fruit juices, soy products, and such vegetables as green beans, corn, carrots, and cabbage. Alcoholic beverages such as wine and beer also contain vanadium. Over-dosing on the vanadium contained in food is not considered a significant risk because the mineral is present only in very small amounts in plants and animals.

Precautions

It is important not to exceed the recommended intake of vanadium without medical supervision. Studies conducted in rats suggest that high dosages of vanadium can be harmful. This results from the fact that the mineral tends to build up in the body, reaching dangerously high levels when taken in excess. The reader should keep in mind that high dosages of vanadium have not yet been proven to have significant health benefits. The long-term health risks associated with taking vanadium supplements (in any dosage) are unknown.

Side effects

When taken in recommended dosages, vanadium has not been associated with any significant or bothersome side effects. At high dosages, vanadium has been known to cause stomach cramping and diarrhea as well as a green tongue.

Interactions

No drugs are known to interact adversely with vanadium. Smokers may absorb less of the mineral.

Resources

BOOKS

Atkins, Robert C. Dr. Atkins' Vita-Nutrient Solution. New York: Simon & Schuster, 1998.

Miller, Lucinda G., and Wallace J. Murray. Herbal Medicinals: A Clinician's Guide. New York: Pharmaceutical Products Press, 1998.

Sifton, David W. PDR Family Guide to Natural Medicines and Healing Therapies. New York: Three Rivers Press, 1999.

ORGANIZATIONS

Herb Research Foundation. 1007 Pearl Street, Suite 200. Boulder, CO 80302.

National Diabetes Information Clearinghouse. 1 Information Way. Bethesda, MD 20892-3560.

OTHER

Discovery Health. http://www.discoveryhealth.com.

National Institute of Diabetes and Digestive and Kidney Diseases. http://www.niddk.nih.gov.

Greg Annussek

VANADIUM (REVISED)

Note: This article, originally published in 1998, was updated in 2006 for the eBook edition.

Overview

Vanadium is a transition metal that lies toward the middle of the periodic table. The periodic table is a chart that shows how chemical elements are related to one another. Groups 4 through 12 are the transition metals.

Vanadium was discovered in 1801 by Spanish-Mexican metallurgist Andrés Manuel del Río (1764-1849). The element was re-discovered nearly 30 years later by Swedish chemist Nils Gabriel Sefstrom (1787-1845).

By far the most important application of vanadium today is in making alloys. An alloy is made by melting and mixing two or more metals. The mixture has properties different from those of the individual metals. Vanadium steel, for example, is more resistant to wear than ordinary steel. A potentially important new use of vanadium is in the manufacture of batteries. These batteries show promise for use in electric cars.

SYMBOL
V

ATOMIC NUMBER
23

ATOMIC MASS
50.9415

FAMILY
Group 5 (VB)
Transition metal

PRONUNCIATION
vuh-NAY-dee-um

Discovery and naming

Andrés Manuel del Rio was educated in France, Germany, and England, but moved to Mexico in 1794. There he became professor of mineralogy at the School of Mines in Mexico City.

While studying minerals at the School of Mines, he believed he had found a new element. He announced this discovery in 1801 and suggested the name panchromium, meaning "all colors." The new element formed compounds of many beautiful colors. Del Rio later changed his mind and decided to call the element erythronium. The prefix erytho- means "red."

Del Río sent the mineral he was studying to colleagues in Europe for confirmation of his discovery. Unfortunately, they concluded that del Río's "new element" was chromium. Del Río's became discouraged and gave up his claim to the new element.

About thirty years later, however, del Río's element was discovered again. This time, the element was found by Sefström, who found the element in iron ore taken from a Swedish mine. He soon realized that his discovery was identical to that of del Rio's. Vanadium was eventually named for the Scandinavian goddess of love, Vanadis.

Both Sefström and del Rio saw vanadium only in the form of a compound, vanadium pentoxide (V₂O₅). It is very difficult to separate pure vanadium metal from this compound. It was not until 1887 that pure vanadium metal was isolated. English chemist Sir Henry Enfield Roscoe (1833-1915) found a way to separate pure vanadium from its oxide.

Physical properties

Vanadium is a silvery-white, ductile, metallic-looking solid. Ductile means capable of being drawn into thin wires. Its melting point is about 1,900°C (3,500°F) and its boiling point is about 3,000°C (5,400°F). Its density is 6.11 grams per cubic centimeter.

Chemical properties

Vanadium is moderately reactive. It does not react with oxygen in the air at room temperatures, nor does it dissolve in water. It does not react with some acids, such as hydrochloric or cold sulfuric acid. But it does become more reactive with hot acids, such as hot sulfuric and nitric acids.

Vanadium is special in that it acts like a metal in some cases, and as a non-metal in other cases. Metals are defined as elements that have a shiny surface, are good conductors of heat and electricity, can be melted, hammered into thin sheets, and drawn into thin wires. Non-metals generally do not have these properties.

Occurrence in nature

Vanadium is a relatively abundant element, ranking about 20th among elements occurring in the Earth's crust. Its abundance has been estimated at about 100 parts per million. That makes it about as abundant as chlorine, chromium, and nickel.

Vanadium is named after the Scandinavian goddess of love, Vanadis.

Vanadium is found in a number of minerals, including vanadinite, carnotite, roscoelite, and patronite. Commercially, however, it is obtained as a by-product of the manufacture of iron. Slag and fly ash are purified to remove the vanadium metal contained within them. Slag is a mixture of materials that separates from iron and floats on top of the molten metal. Fly ash is a powdery material produced during the purification of iron.

The vanadium obtained from slag and fly ash is usually in the form of ferrovanadium. Ferrovanadium is a mixture of iron and vanadium. It can be used in place of pure vanadium in making alloys. Ferrovanadium saves companies the cost of making pure vanadium metal.

Isotopes

Two naturally occurring isotopes of vanadium exist, vanadium-50 and vanadium-51. Vanadium-51 is much more common, making up about 99.75 percent of all naturally occurring vanadium.

Isotopes are two or more forms of an element. Isotopes differ from each other according to their mass number. The number written to the right of the element's name is the mass number. The mass number represents the number of protons plus neutrons in the nucleus of an atom of the element. The number of protons determines the element, but the number of neutrons in the atom of any one element can vary. Each variation is an isotope.

Vanadium-50 is radioactive. It has a half life of about 6 quadrillion years. The half life of a radioactive element is the time it takes for half of a sample of the element to break down. Ten grams of vanadium-50 today would reduce by 5 grams after 6 quadrillion years. The other half would have broken down to form a new isotope.

Extraction

Vanadium can be obtained in a variety of ways. For example, it can be produced by passing an electric current through molten (melted) vanadium chloride:

It can also be made by combining calcium metal with vanadium oxide:

Uses

About 90 percent of vanadium goes into steel alloys. Steel containing vanadium is stronger, tougher, and more rust-resistant than steel without vanadium. An important application of such alloys is in space vehicles and aircraft. A common use of vanadium steel alloys is in tools used for cutting and grinding. Overall, about a third of all vanadium steel goes to building and heavy construction uses; less goes to transportation, machinery, and tool applications.

Compounds

The most important compound of vanadium commercially is vanadium pentoxide. Among its applications are as a catalyst for many industrial reactions, as a coloring material for glass and ceramics, and in the dyeing of textiles. A catalyst is a substance used to speed up or slow down a chemical reaction without undergoing any change itself.

An important new use for vanadium pentoxide may be in batteries. Scientists have been working for a very long time to make better batteries. Common automobile batteries are large and heavy. Batteries like these are too big and heavy for many applications. For example, they cannot be used in space probes and space vehicles. They weigh too much.

These batteries are also too large for use in electric cars. An electric car is powered by electricity rather than gasoline. A great deal of research is being done toward the development of an economical electric car.

A new vanadium pentoxide battery produces more electrical energy per pound than the lead storage batteries in cars today. They are also likely to cause fewer environmental disposal problems.

Some manufacturers think electric cars with vanadium pentoxide batteries are part of the world's transportation future. Drivers would bring these cars into a "battery filling station." The worn-out battery would be "pumped out" and replaced in a matter of minutes. Economists predict that drivers may spend as much as $6 billion per year for such batteries by 2004!

Health effects

Vanadium occurs in living organisms in very small amounts. The total amount of vanadium in the human body is estimated to be less than 1 milligram (0.000035 ounce). It is found most commonly in the kidneys, spleen, lungs, testes, and bones. No specific function for vanadium in humans has been found.

Diseases due to a lack of vanadium have been found in rats, chicks, and goats, but only under artificial conditions produced by researchers. A lack of vanadium has never been found to have any health effects on any kind of animals in natural settings.

Some manufacturers think electric cars with vanadium pentoxide batteries are part of the world's transportation future.

In large doses, vanadium can be toxic to humans and other animals. Its effects are not very serious, however. In general, the element and its compounds are not considered to be a hazard to health.

Vanadium

melting point: 1,910 ±10°C
boiling point: 3,047°C
density: 6.11 g/cm³
most common ions: V²⁺, V³⁺, VO⁺, VO₂⁺

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 : ⁵⁰V (0.25%) and ⁵¹V (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>.

vanadium (symbol V) Silver-white, metallic element, one of the transition elements. Discovered in 1801, the malleable and ductile metal is found in iron, lead, and uranium ores, and in coal and petroleum. It is used in steel alloys to add strength and heat resistance. Chemically, vanadium reacts with oxygen and other nonmetals at high temperature. Properties: at.no. 23; r.a.m. 50.9414; r.d. 6.1 at 18.7°C; m.p. 1890°C (3434°F); b.p. 3380°C (6116°F); most common isotope V⁵¹ (99.76%).

va·na·di·um / vəˈnādēəm/ • n. the chemical element of atomic number 23, a hard gray metal of the transition series, used to make alloy steels. (Symbol: V)