Tantalum Facts (Atomic Number 73 and Element Symbol Ta)

Tantalum is a blue-gray transition metal with element symbol Ta and atomic number 73. Because of its hardness and corrosion resistance, it is an important refractory metal and is widely used in alloys.

Tantalum Basic Facts

Atomic Number: 73

Symbol: Ta

Atomic Weight: 180.9479

Discovery: Anders Ekeberg in 1802 (Sweden) showed that niobic acid and tantalic acid were two different substances.

Electron Configuration: [Xe] 6s² 4f¹⁴ 5d³

Word Origin: Greek Tantalos, mythological character, king who was father of Niobe. In the afterlife, Tantalos was punished by being forced to stand in knee-deep water with fruit above his head. The water and the fruit tantalized him, as the water would drain if he bent to drink and the fruit would move away if he reached for it. Ekeberg named the metal for its resistance to absorb or react with acid.

Isotopes: There are 25 known isotopes of tantalum. Natural tantalum consists of 2 isotopes: tantalum-180m and tantalum-181. Tantalum-181 is a stable isotope, while tantalum-180m is the only natural nuclear isomer.

Properties: Tantalum is a heavy, hard gray metal. Pure tantalum is ductile and may be drawn into very fine wire. Tantalum is practically immune to chemical attack at temperatures lower than 150 °C. It is only attacked by hydrofluoric acid, acidic solutions of the fluoride ion, and free sulfur trioxide. Alkalis attack tantalum very slowly. At higher temperatures, tantalum is more reactive. The melting point of tantalum is very high, exceeded only by that of tungsten and rhenium. The melting point of tantalum is 2996 °C; boiling point is 5425 +/- 100 °C; specific gravity is 16.654; valence is usually 5, but may be 2, 3, or 4.

Uses: Tantalum wire is used as a filament for evaporating other metals. Tantalum is incorporated into a variety of alloys, conferring high melting point, ductility, strength, and corrosion resistance. Tantalum carbide is one of the hardest materials ever made. At high temperatures, tantalum has good 'gettering' ability. Tantalum oxide films are stable, with desirable dielectric and rectifying properties. The metal is used in chemical process equipment, vacuum furnaces, capacitors, nuclear reactors, and aircraft parts. Tantalum oxide may be used to make a glass with a high index of refraction, with applications including use for camera lenses. Tantalum is immune to body liquids and is a non-irritating metal. Therefore, it has widespread surgical applications. Tantalum is a technology-critical element, as it is used in computers, cell phones, and other electronic equipment.

Sources: Tantalum is found primarily in the mineral columbite-tantalite (Fe, Mn)(Nb, Ta)₂O₆ or Coltan. Coltan is a conflict resource. Tantalum ores are found in Australia, Zaire, Brazil, Mozambique, Thailand, Portugal, Nigeria, and Canada. A complicated process is required to remove tantalum from the ore, as tantalum always occurs with niobium. Tantalum is estimated to occur at an abundance of about 1 ppm or 2 ppm in the Earth's crust.

Biological Role: While tantalum serves no biological role, it is biocompatible. It is used to make body implants. Exposure to the metal tends to occur via breathing, eye contact, or skin contact. The metal's environmental impact is not well-understood.

Element Classification: Transition Metal

Tantalum Physical Data

Density (g/cc): 16.654

Melting Point (K): 3269

Boiling Point (K): 5698

Appearance: heavy, hard gray metal

Atomic Radius (pm): 149

Atomic Volume (cc/mol): 10.9

Covalent Radius (pm): 134

Ionic Radius: 68 (+5e)

Specific Heat (@20°C J/g mol): 0.140

Fusion Heat (kJ/mol): 24.7

Evaporation Heat (kJ/mol): 758

Debye Temperature (K): 225.00

Pauling Negativity Number: 1.5

First Ionizing Energy (kJ/mol): 760.1

Oxidation States: 5

Lattice Structure: Body-Centered Cubic

Lattice Constant (Å): 3.310

Sources

• Emsley, John (2011). Nature's Building Blocks: An A-Z Guide to the Elements. Oxford University Press. ISBN 978-0-19-960563-7.
• Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
• Hammond, C. R. (2004). The Elements, in Handbook of Chemistry and Physics (81st ed.). CRC press. ISBN 978-0-8493-0485-9.
• Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. ISBN 0-8493-0464-4.
• Wollaston, William Hyde (1809). "On the Identity of Columbium and Tantalum." Philosophical Transactions of the Royal Society of London. 99: 246–252. doi:10.1098/rstl.1809.0017