Tantalum Element Facts – Ta or Atomic Number 73


Tantalum Element Facts

Tantalum is a chemical element with the symbol Ta and atomic number 73. It is a rare, hard, blue-gray, lustrous transition metal that is highly corrosion-resistant. Tantalum is important in electronics, so you encounter it in capacitors and high-power resistors. Other uses include camera lens coating and hip replacements.

Discovery, Naming, and Isolation

Tantalum was discovered in 1802 by Swedish chemist Anders Gustaf Ekeberg. The element was named after Tantalus, a figure from Greek mythology, because of its inability to absorb acids, much like Tantalus was unable to drink water. Early on, tantalum was often confused with niobium due to their chemical similarities. Heinrich Rose definitively recognized tantalum as a distinct element in 1844. Charles Galissard de Marignac was the first person to isolate purified tantalum metal in 1864.

Tantalum Appearance and Properties

Tantalum is a dense, hard, ductile, and highly conductive blue-gray metal. It has a body-centered cubic crystal structure at room temperature. The other crystal phase occurs upon heating the element and has a tetragonal crystal structure. The metal is known for its high melting point, which is 3017°C (5463°F), making it one of the most heat-resistant metals.

Chemical Properties

Tantalum is highly corrosion-resistant due to the formation of a stable oxide layer (Ta2O5). It is inert to most acids but dissolves in hydrofluoric acid. Tantalum resists attack by aqua regia at temperatures below 150°C. Hot alkalis only slightly affect it. Chemically, the element most closely resembles niobium, which sits above it on the periodic table.

Electron Levels of a Tantalum Atom

Element Group

Tantalum belongs to Group 5 (VB) of the periodic table, alongside vanadium, niobium, and dubnium. It is part of the d-block elements and is a transition metal. It is in period 6 of the periodic table.

Tantalum Isotopes

Tantalum has two natural isotopes:

  • Tantalum-181 (Ta-181): The most abundant isotope, constituting nearly 99.988% of natural tantalum. It is stable.
  • Tantalum-180m (Ta-180m): A rare isotope that exists in a metastable state. It constitutes about 0.012% of natural tantalum. It is quasi-stable with a very long half-life.

There are synthetic isotopes of tantalum, such as Ta-182, but they have relatively short half-lives and are used primarily for research purposes. One potential use of radioisotopes is for salting nuclear weapons. Basically, the weapon produces radioactive tantalum and increases the radioactivity of nuclear fallout.

Abundance

Tantalum is a rare element in the Earth’s crust, with an average abundance of about 2 ppm (parts per million).

Sources

Tantalum comes from several mineral sources, with the most significant ones being:

  • Tantalite ((Fe,Mn)(Ta,Nb)2O6): A major ore of tantalum that is common in granite pegmatites.
  • Columbite (Fe,Mn)(Nb,Ta)2O6: Often occurs with tantalite, and the two are collectively referred to as coltan.
  • Microlite (Na,Ca)2Ta2O6(O,OH,F): Another source of tantalum in granitic pegmatites.

Major tantalum-producing countries include Australia, Brazil, Canada, Mozambique, and Rwanda.

Purification

Tantalum purification is a complex process involving several steps:

  1. Mining and Concentration: The first step is mining and concentrating tantalum-containing ores.
  2. Decomposition: Either acidic or alkali treatment decomposes the concentrate.
  3. Solvent Extraction: Solvent extraction separates tantalum from niobium and other impurities.
  4. Reduction: A reducing agent like sodium or magnesium yields metallic tantalum from its compound.
  5. Electron Beam Melting: The final purification step involves melting the metal in an electron beam furnace. This treatment removes any remaining impurities.

Tantalum Uses

The element tantalum has a wide range of applications, primarily due to its corrosion resistance and electrical properties:

  • Electronics: Tantalum is important in the production of capacitors and high-power resistors, which are essential for mobile phones, computers, and other electronic devices.
  • Aerospace and Military: The metal finds use in high-performance alloys for aircraft engines and other critical components. Both Voyager 1 and Voyager 2 made use of tantalum shielding.
  • Medical Devices: Because of its biocompatibility, tantalum is useful in surgical instruments and implants, such as hip replacements.
  • Chemical Processing Equipment: The element finds use in the production of heat exchangers, reactors, and other equipment that withstand corrosive environments.
  • Superalloys: Adding tantalum to nickel-based superalloys improves high-temperature strength and corrosion resistance.
  • Optical Coatings: The element is important in the production of thin films for camera lenses and other optical devices.
  • Tantalum Carbide: This extremely hard compound occurs in cutting tools and wear-resistant parts.
  • Decorations: Jewelry, watches, and commemorative coins use the element for its beautiful color and biocompatibility.

Oxidation States

Tantalum commonly exhibits oxidation states of +5 and +4, with the +5 state being the most stable and prevalent. The other oxidation states are less common.

Biological Role

Tantalum has no known biological role in humans or other organisms. It is mostly inert and biocompatible, which is why it is used in medical implants. Bone cells integrate into porous metal surface. Since the metal is not magnetic, it does not pose a problem with MRIs or metal detectors.

Tantalum Health Effects and Toxicity

Tantalum is generally non-toxic and safe for human exposure. However, fine particulate forms of tantalum (such as dust or powder) pose inhalation risks.

There is limited information on the toxicity of tantalum to other organisms. It is generally low in toxicity and environmentally benign.

Key Tantalum Facts

PropertyValue
NameTantalum
SymbolTa
Atomic Number73
Atomic Weight180.94788
Group5 (VB)
Period6
Blockd-block
Electron Configuration[Xe] 4f14 5d3 6s2
Electrons per Shell2, 8, 18, 32, 11, 2
State at 20°CSolid
Melting Point3017°C (5463°F)
Boiling Point5458°C (9856°F)
Density16.68 g/cm³
Heat of Fusion36.57 kJ/mol
Heat of Vaporization753 kJ/mol
Molar Heat Capacity25.36 J/mol·K
Oxidation States-3, -1, 0, +1, +2, +3, +4, +5 (main state: +5)
Electronegativity1.5 (Pauling scale)
First Ionization Energy761 kJ/mol
Second Ionization Energy1500 kJ/mol
Third Ionization Energy3100 kJ/mol
Atomic Radius146 pm
Covalent Radius170 pm
Crystal StructureBody-centered cubic (bcc)
Thermal Conductivity57.5 W/m·K
Electrical Resistivity131 nΩ·m at 20°C
Magnetic OrderingParamagnetic
Young’s Modulus186 GPa
Shear Modulus69 GPa
Mohs Hardness6.5

Tantalum as a Conflict Resource

Tantalum from the mineral coltan (columbite-tantalite) is a conflict resource due to its association with armed conflict and human rights abuses, particularly in the Democratic Republic of Congo (DRC). The high demand for tantalum in the electronics industry fuels its illegal mining and trade, often controlled by armed groups who use the proceeds to fund their activities. There are significant social and environmental issues associated with coltan, including exploitation, forced labor, child labor, and environmental degradation.

In response to these issues, various initiatives and regulations are in place to improve responsible sourcing of this element. The Dodd-Frank Wall Street Reform and Consumer Protection Act, for example, requires that companies disclose the use of conflict minerals (including tantalum) sourced from the DRC and neighboring countries. Additionally, industry-led initiatives like the Responsible Minerals Initiative (RMI) promote responsible sourcing practices and traceability in the supply chain to minimize the impact of conflict minerals. Even so, the situation remains complex.

Recycling

Tantalum is highly recyclable from used electronic devices and other products. Recycling not only conserves natural resources but also reduces environmental impact.

Future Prospects

The demand for tantalum grows with the increasing need for electronic devices, renewable energy technologies, and advanced materials. Research continues into new applications and more efficient extraction methods.

References