Elements of group 5

Group 5 (according to IUPAC nomenclature) is a group of chemical elements on the periodic table. Group 5 contains vanadium (V), niobium (Nb), tantalum (Ta), and dubnium (Db). This group is located in the d block of the periodic table. The group itself has not acquired a trivial name; It belongs to the larger group of transition metals.

The three lightest elements in Group 5 occur naturally and share similar properties; all three are hard refractory metals at standard conditions. The fourth element, dubnium, has been synthesized in laboratories, but has not been found to occur in nature, with the half-life of the most stable isotope, dubnium-268, being only 29 hours, and other isotopes even more radioactive. To date, no experiments have been performed in a supercollider to synthesize the next member of the group, either unpentseptium (Ups) or unpentennium (Upe). Since unpentenium and unpentenium are late period 8 elements it is unlikely that these elements will be synthesized in the near future.

A group 5 element is an element located within the periodic table in group 5 that includes the elements:

• vanadium (23)
• Niobio (41)
• Tantalo (73)
• Dubnio (105)

These elements have 5 electrons in their outermost electronic levels. Dubnium is not found in nature and is produced in the laboratory, so when talking about the properties of the group 5 elements, this element is usually ignored.

Chemistry

Like other groups, members of this family exhibit patterns in their electron configuration, especially the outer shells, although niobium curiously does not follow the trend:

Most of the chemistry has been observed for only the first three members of the group, the chemistry of dubnium is not well established, and therefore the remainder of the section deals only with vanadium, niobium, and tantalum. All elements in the group are reactive metals with a high melting point (1910 °C, 2477 °C, 3017 °C). Reactivity is not always obvious due to the rapid formation of a stable oxide layer, which prevents further reactions, similar to trends in Group 3 or Group 4. Metals form different oxides: vanadium forms vanadium oxide (II), vanadium(III) oxide, vanadium(IV) oxide and vanadium(V) oxide, niobium forms niobium(II) oxide, niobium(IV) oxide and niobium(V) oxide but from tantalum oxides only tantalum(V) oxide is characterized. Metal(V) oxides are generally unreactive and act as acids rather than bases, but the lower oxides are less stable. However, they have some unusual properties for oxides, such as high electrical conductivity.

The three elements form various inorganic compounds, usually in the +5 oxidation state. Lower oxidation states are also known, but they are less stable, their stability decreasing with increasing atomic mass.

History

Vanadium was discovered in 1801 by Andrés Manuel del Río, a Spanish-born Mexican mineralogist, in the mineral vanadinite. After other chemists rejected his discovery of erythronium he withdrew the claim from him.

Niobium was discovered by English chemist Charles Hatchett in 1801.

Tantalum was discovered in 1802 by Anders Gustav Ekeberg. However, it was thought to be identical to niobium until 1846, when Heinrich Rose showed that the two elements were different. Pure tantalum could only be produced in 1903.

Dubnium was first produced in 1968 at the Joint Institute for Nuclear Research by bombarding americium-243 with neon-22 and was produced again at Lawrence Berkeley Laboratory in 1970. The names "neilsbohrium" and "joliotium" were proposed for the element, but in 1997, the IUPAC decided on the element's name dubnium.

Etymologies

Vanadium is named after Vanadis (or Freyja), the Scandinavian goddess of love. Niobium owes its name to Niobe, a character from Greek mythology. Tantalum owes its name to Tantalus, a character from Greek mythology. Dubnium's name refers to Dubna, Russia, where it was discovered.

Occurrence

There are 160 parts per million of vanadium in the earth's crust, making it the 19th most abundant element there. Soil contains on average 100 parts per million vanadium, and seawater contains 1.5 parts per billion vanadium. A typical human contains 285 parts per billion of vanadium. More than 60 vanadium minerals are known, including vanadinite, patronite, and carnotite.

There are 20 parts per million of niobium in Earth's crust, making it the 33rd most abundant element there. The soil contains an average of 24 parts per million of niobium and seawater contains 900 parts per quadrillion of niobium. A typical human being contains 21 parts per billion of niobium. Niobium is found in the minerals columbite and pyrochlore.

There are 2 parts per million of tantalum in the Earth's crust, making it the 51st most abundant element there. Soil contains on average 1 to 2 parts per billion of tantalum, and seawater contains 2 parts per billion of tantalum. A typical human contains 2.9 parts per billion of tantalum. Tantalum is found in the minerals tantalite and pyrochlore.

Uses

The main use of vanadium is in alloys, such as vanadium steel. Vanadium alloys are used in springs, tools, jet engines, armor plating, and nuclear reactors. Vanadium oxide gives ceramics a golden color, and other vanadium compounds are used as catalysts to produce polymers.

Small amounts of niobium are added to stainless steel to improve its quality. Niobium alloys are also used in rocket nozzles due to niobium's high corrosion resistance.

Tantalum has four main types of applications. Tantalum is added to the material of objects exposed to high temperatures, in electronic devices, in surgical implants, and to handle corrosive substances.

Toxicity

Pure vanadium is not known to be toxic. However, vanadium pentoxide causes severe irritation to the eyes, nose, and throat.

Niobium and its compounds are thought to be mildly toxic, but niobium poisoning is not known to have occurred. Niobium dust can be irritating to eyes and skin.

Tantalum and its compounds rarely cause lesions, and when they do, the lesions are usually rashes.

For more information

• Greenwood, N (2003). «Vanadium to dubnium: from confusion through clarity to complexity». Catalysis Today 78 (1–4): 5-11. doi:10.1016/S0920-5861(02)00318-8.