The Element Vanadium
Vanadium is a silver, ductile element belonging to group 5 on the periodic table. It is resistant to corrosion, making it a fairly strong transition metal. Named after the Scandinavian goddess of beauty, Vanadis, the element vanadium truly lives up to its name. Being a polyvalent transition metal, vanadium forms beautiful, colorful compounds. However, you must be careful of these magnificent compounds, as they can be toxic to humans. Let’s further explore this intriguing element.
Cool Facts About Vanadium
- The first industrial usage of vanadium steel was in 1908. Henry Ford appreciated the strength of vanadium steel and made it the primary material for the Ford Model T- the first car to be made via assembly line.
- Vanadium was discovered twice.
- Large amounts of its compounds can be toxic. Those that encounter higher exposure to vanadium are more prone to eye, nose, and throat irritation. Inhaling too much may lead to problems in the lungs, like bronchitis and pneumonia.
- Small percentages of vanadium are found in meteorites.
- Vanadium is sometimes combined with gallium to form superconductive magnets.
Vanadium on the Periodic Table
Vanadium has atomic symbol V, and atomic number 23. It is a transition metal that lies to the left of chromium, the right of titanium, and above niobium. It is used mostly as a steel additive. The vanadium atom has an electron configuration of [Ar]3d34s2 or 1s22s22p63s23p63d34s2
Where is Vanadium Found in Nature
The element compromises about 150 ppm of the Earth’s core and roughly 0.019% of the earth’s crust. However, it is rare to find pure vanadium freely in nature. Instead, it always occurs in a type of compound, like vanadinite, magnetite, patronite, carnotite, and more than 60 other minerals. It also exists in crude oil, coal, and phosphate rocks. China, Russia, and South Africa are the top three miners of vanadium ores, as they are responsible for 98% of it, worldwide.
There are 26 isotopes of vanadium but only two are naturally occurring: vanadium-50 and vanadium-51. Vanadium-50 has an abundance of 0.20%, which seems mere compared to vanadium-51, which has an abundance of about 99.76%. To compare them even more, vanadium-50 is radioactive and has a half-life greater than 2.1 x 1017 years, while vanadium-51 is non-radioactive and is the only stable isotope. Vanadium-50 has much use in geological research, as it is needed for the neutron activation analysis of rock and ore samples. It also has a role in heterogeneous catalysis, as it analyzes the intermediates in the reaction. Vanadium-51 is significant for medical and nuclear physics research.
Biological Role of Vanadium
Vanadium, a trace mineral, is thought to be essential for humans in just microgram quantities. Foods like mushrooms, grains, parsley, and even beer and wine contain some vanadium, and humans consume about 0.01 milligrams per day. Humans may need very small amounts to promote normal bone growth. Studies are still being conducted on how vanadium affects the body, emphasizing the “may need”. However, larger doses of vanadium may be present in medications, especially for glucose metabolism and insulin regulation.
Vanadium mimics insulin and according to “Vanadium & Diabetes, Benefit or Harm?”, can even replace insulin (check out their article here). Vanadium can help both Type 1 and Type 2 diabetic patients by improving insulin sensitivity. There are also many other benefits that vanadium is thought to exhibit, including lowering cholesterol levels, lowering blood pressure, and reducing the production of prostate cancer cells.
However, there are drawbacks to the effects vanadium has on the body. Vanadium has an anion called vanadate (v), which is structurally similar to the phosphate anion. Therefore, vanadate functions as a nonspecific competitive inhibitor of phosphatase. This means that vanadate can bind to a binding pocket of a substrate that would otherwise bind to a phosphate anion to produce an effect. Therefore, vanadate has the ability to inhibit some regulatory functions that depend on phosphatase. The benefits of using vanadium in medicine are still inconclusive, but there is definitely a lot of potential.
Vanadium’s Applications in Today’s World
Vanadium is one of the lesser-known metals, despite some of its great properties, including its malleability and resistance to corrosion. The primary use of vanadium is as a steel alloy additive; About 80% is used as ferrovanadium, which is an iron alloy consisting of anywhere between 35% to 80% of vanadium. Adding vanadium to other metals is beneficial because just a small amount can tremendously increase its strength and resistance to corrosion while adding little weight. In addition, products containing vanadium are rust-resistant. Alloys like ferrovanadium are commonly used in the production of tool steels and vehicle parts, like car hoods. Vanadium is also added to titanium alloys to promote strength and protection from temperature changes (learn more about titanium here). The aviation industry prefers vanadium-titanium alloys for the production of its jet engines and spacecrafts.
Additionally, it possesses low neutron absorption abilities, making it applicable for nuclear reactors. At the Russian National University of Science and Technology, material scientists have developed a steel-vanadium alloy for the purpose of it being used in the shells of nuclear reactor cores. Having vanadium as part of the steel alloy adds heat and radiation resistance for protection against the rather harsh environment of nuclear reactors.
Vanadium also makes dye- specifically aniline black. Vanadium salts, like vanadous chloride and vanadate of ammonia, are combined with a mixture of aniline black, resulting in the solution darkening and deposits of aniline black to be released. After about 48 hours, the final product will have solidified into a thick, black paste. Aniline black can be used to dye cotton, silk, proteinaceous fibers, and is used for printing ink. Vanadium is also a colorant agent for ceramics and glass. It is sometimes added to transparent glass-ceramics to darken it. It can also give the glass a pretty green tint. Furthermore, coating ceramics with vanadium is preferable for heat resistance.
The second most important application of vanadium is its role as a catalyst. For example, to make sulfuric acid, sulfur dioxide has to first convert to sulfur trioxide. To do this, sulfur dioxide must be oxidized to a trioxide in the presence of vanadium oxide-containing air. The reason that vanadium is able to function as a catalyst is because it can change its oxidation number; When sulfur dioxide changes to sulfur trioxide, vanadium (V) oxide reduces to vanadium (IV) oxide, and then re-oxidzes to vanadium (V).
History of Vanadium
How was Vanadium discovered, and by who?
Vanadium has an interesting history and was even discovered twice. In 1794, a Spanish-Mexican mineralogist, Andrés Manuel Del Río, was offered the chair of mineralogy at the Royal School of Mines in Mexico City. Here, he was responsible for analyzing the chemistry of new minerals. In 1801, he found a brown lead ore from a mine named La Purísima del Cardenal, resulting in his discovery of a new element, which we would know as vanadium. However, at the time, Del Río called his element panchromium, meaning “all of the colors” because of the element’s colorful salts. He later renamed the element erythronium, after the Greek word, “eruthros”, meaning red, because Group 1 and Group 2 oxide salts of the element would turn red when heated.
A few years later, in 1805, French chemist Hippolyte-Victor Collet-Descotils examined the same brown lead ore and stated that erythronium was actually impure chromium. Unfortunately, Del Río agreed that he was wrong about his finding. It was not until 1830 when a Swedish chemist named Nils Gabriel Sefström found an iron ore and discovered an element. He named this “new” element vanadium, after ‘Vanadis’, the Scandinavian goddess of beauty. Not long after, German chemist Friedrich Wöhler analyzed Del Río’s brown lead ore with Sefström’s iron ore and realized that the two “different” elements were actually identical.
Vanadium is a moderately reactive element that acts as both a metal and nonmetal in certain reactions. It becomes more reactive at elevated temperatures; In normal conditions, vanadium is unaffected by oxygen and water because of its protective oxide layer. It is also resistant to molten alkali metal.
When heated, vanadium metal reacts with excess oxygen in the air to form vanadium(V) oxide, V2O5. Vanadium metal is quite reactive at elevated temperatures, resulting in the possibility of the vanadium(V) oxide containing other vanadium oxides as well. Lower oxidation states of vanadium may re-oxidize, until no longer exposed to oxygen.
It is only reactive with certain acids, which act as oxidizing agents. When vanadium(II) combines with an acid, it produces blue-colored dioxovanadium(V), VO2+, ions. When ammonium metavanadate, NH4VO3 combines with hot hydrochloric acid, it forms a reddish-brown chloro-complex and reduces the compound to a +4 oxidation state.
Fluorine, F2, a halogen, will react with vanadium at elevated temperatures. When fluorine and vanadium react, it produces the colorless vanadium(V) fluoride. This compound is extremely reactive and will vaporize easily.
There are several compounds that vanadium exists in. They present themselves in a wide range of colors, explaining why the element was named after the Scandinavian goddess of beauty.
Vanadium oxides play a large role in the industrial field for their resistance to corrosion and rust. Their primary use is in steel alloys, called ferrovanadium alloys. At temperatures above 660˚C (1220˚F), vanadium oxide metals become reactive and will readily oxidize. Interestingly, each oxidation state associates itself with a specific color.
Vanadium monoxide, VO is an electronically neutral reagent. It comes as a grey metallic solid and is an electrical conductor with a high melting point of 1789˚C (3252.2˚F). Its solution is a purple color that oxidizes to vanadium(III) when exposed to air, changing the color to green. Additionally, adding nitric acid to vanadium(II) solution can produce blue colored vanadyl ions, VO2+.
Vanadium trioxide, V2O3, is a black, crystalline solid that is slightly soluble in water. This basic oxide occurs naturally in karelianite mineral. Additionally, it functions as a reducing agent. When exposed to air, vanadium trioxide oxides decompose to the blue colored vanadium(IV) state.
Vanadium dioxide, VO2, is amphoteric, meaning it is able to behave as both a base and acid. When put into an acid solution, vanadium dioxide dissociates into blue-colored vanadyl ions, VO2+. In a base solution, vanadium dioxide produces yellowish-brown colored hypovanadate ions, [V4O9]2-.
Vanadium pentoxide, V2O5, is vanadium’s most important compound because of its thermal stability and abundance. It has a density of 3.35 g/cm3 and is not very soluble in water. This yellow to red crystalline powder has several functions, including being a mordant, acting as a catalyst for some chemical reactions, being useful in the production of ceramics, and forming superconductive magnets with gallium. Despite its widespread applications, this compound can be toxic when ingested, inhaled, or in contact with skin. Ammonium metavanadate, NH4VO3, a compound where vanadium presents itself in the +5 oxidation state, can be reduced under acidic conditions. Adding zinc and a moderately concentrated acid will reduce vanadium(V) to vanadium (IV).
Vanadium-containing minerals, like carnotite, are processed to isolate vanadium. First, the carnotite ore goes through a leaching process, where it gets treated with hot sulfuric acid and an oxidizing agent for 24 hours. The leaching process works to convert vanadium into a soluble salt. Notably, uranium is also found in carnotite, and therefore, uranium salts are also extracted. The salts then get filtered out and the remaining “ore” is further processed. This isolates vanadium from uranium, allowing for vanadium to go through a precipitation reaction with ammonium sulfate. This precipitation reaction produces ammonium metavanadate. Lastly, ammonium metavanadate is filtered out and calcined to vanadium pentoxide.
Isolation of Vanadium
Titaniferous magnetite is the primary source of vanadium. These ores first react with coal in a rotary kiln. This reduces titaniferous magnetite into slag, which is a waste product consisting of titanium, and crude iron, which consists of vanadium. The vanadium-containing iron is removed and mixed with oxygen at elevated temperatures, producing vanadium pentoxide.
Vanadium Oxidation States
Vanadium compounds exist in oxidation states of +5, +4, +3, and +2, with the +5 state dominating. The +5 oxidation state of vanadium is usually in the form of ammonium metavanadate, NH4VO3. This compound is fairly insoluble and dissolves in sodium hydroxide solutions. To reduce ammonium metavanadate to the +4 oxidation state, zinc and an acid, such as hydrochloric acid, react with the compound. Uniquely, these oxidation states distinguish themselves with different colors. The +5 state is yellow; the +4 state is blue; the +3 state is green; and the +2 state is purple.
Physical Properties of Vanadium
- Melting point: 2183 K; 1910°C; 3470°F
- Boiling point: 3680 K; 3407°C; 6165°F
- Density: 6.0 g/cm3
- Atomic Symbol: V
- Atomic weight: 50.942
- Atomic number: 23
- Electronegativity: 1.63
- Classification: Transition metal
- Natural abundance in the Earth’s crust: 0.019%
- Electron shell configuration: [Ar] 3d3 4s2
- Isotopes: Vanadium-50 and vanadium-51 are naturally occurring
- Found naturally in the minerals: Vanadium is found in 65 different minerals, including vanadinite, carnotite, and magnetite
- Toxicity: Non-toxic to humans at normal concentrations, but its compounds can be toxic
Where can I buy it?
High purity vanadium metal crystals can be purchased from Amazon and specialty shops.