Tantalum
Atomic Data
| Atomic Number | 73 |
| Symbol | Ta |
| Atomic Weight | 180.95 u |
| Density (STP) | 16.69 g/cm³ |
| Melting Point | 3016.85 °C (3290 K) |
| Boiling Point | 5457.85 °C (5731 K) |
| Electronegativity | 1.5 (Pauling) |
| Electron Config. | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d3 6s2 |
| Oxidation States | +5 |
| Phase at STP | Solid |
| Category | Transition Metal |
| Period / Group | 6 / 5 |
| CAS Number | 7440-25-7 |
Electron Configuration
[Xe] 4f14 5d3 6s2
| Shell | n | Subshell | Electrons | Cumulative |
|---|---|---|---|---|
| K | 1 | 1s | 2 | 2 |
| L | 2 | 2s | 2 | 4 |
| L | 2 | 2p | 6 | 10 |
| M | 3 | 3s | 2 | 12 |
| M | 3 | 3p | 6 | 18 |
| M | 3 | 3d | 10 | 28 |
| N | 4 | 4s | 2 | 30 |
| N | 4 | 4p | 6 | 36 |
| N | 4 | 4d | 10 | 46 |
| N | 4 | 4f | 14 | 60 |
| O | 5 | 5s | 2 | 62 |
| O | 5 | 5p | 6 | 68 |
| O | 5 | 5d | 3 | 71 |
| P | 6 | 6s | 2 | 73 |
| Total | 73 | 73 | ||
Isotopes of Tantalum
Tantalum has two naturally occurring stable isotopes. The most abundant is ¹⁸¹Ta, comprising 99.98799% of all naturally occurring Tantalum.
| Isotope | Symbol | Protons | Neutrons | Abundance | Stability |
|---|---|---|---|---|---|
| Tantalum-180 | ¹⁸⁰Ta | 73 | 107 | 0.01201 | Stable |
| Tantalum-181 | ¹⁸¹Ta | 73 | 108 | 99.98799 | Stable |
Abundance & Occurrence
Tantalum is present in Earth's crust at approximately 2 ppm by mass and at approximately 0.002 ppm by mass throughout the universe.
Earth's Crust (ppm by mass)
Universe (ppm by mass)
Discovery & History
Read more about the discovery of the periodic table of elements →
Safety & Handling
- Tantalum oxide dust: Ta2O5 dust is a mild respiratory irritant; as with other refractory metal oxides, chronic high-level inhalation should be controlled with ventilation and respiratory protection.
- Tantalum pentachloride: TaCl5 reacts with moisture to produce HCl; it is corrosive and requires dry, ventilated handling.
- Metal powder fire hazard: Fine tantalum powder is flammable and can cause dust explosions; handle powder operations with inert gas and Class D fire suppression.
- Biocompatibility: Bulk tantalum is highly biocompatible and is used in surgical implants; its low systemic toxicity and corrosion resistance make it one of the safest metals for implant applications.
Tantalum in the Real World
Real-World Uses
- Tantalum capacitors: Tantalum powder is sintered into porous pellets, anodically oxidised to form a dielectric Ta₂O₅ film, and assembled into capacitors that provide high capacitance in a tiny volume; tantalum capacitors are in virtually every smartphone, laptop, and implantable medical device.
- Biomedical implants: Tantalum is chemically inert in body fluids, biocompatible, and visible on X-ray; used as bone plates, craniofacial mesh, stents, and porous trabecular metal scaffolds that allow bone to grow directly into the implant for orthopaedic and craniofacial reconstruction.
- Corrosion-resistant chemical equipment: Tantalum's resistance to nearly all mineral acids makes it the material of choice for heat exchangers, bayonet heaters, column liners, and valves handling corrosive chemicals in the chemical processing industry.
- Superalloy additive: Tantalum (2–6%) stabilises the gamma-prime strengthening phase in nickel superalloys used in the hottest sections of jet turbine blades, improving creep resistance and allowing higher turbine inlet temperatures.
- Carbide cutting tools: Tantalum carbide (TaC) is added to cemented carbide inserts to improve resistance to crater wear at high cutting speeds and to reduce the tendency of carbide tools to weld to the steel workpiece.
Downloadable Resources
Free periodic table reference sheets for classrooms, study sessions, and laboratory use.
Frequently Asked Questions
What is tantalum used for?
Tantalum's largest use is in capacitors: tantalum electrolytic capacitors are compact and have high capacitance per volume, making them essential in smartphones, laptops, and other portable electronics. Tantalum is also used in surgical implants and medical instruments because of its excellent biocompatibility and corrosion resistance. It is used in superalloys for jet turbine components and in chemical processing equipment that must resist aggressive acids.
Is tantalum linked to conflict minerals?
Yes. Coltan (columbite-tantalite ore) is mined extensively in the Democratic Republic of Congo, and during the early 2000s armed groups were known to control mines and profit from coltan sales, fuelling conflict. The 'blood coltan' issue drew international attention and led to regulatory responses including the Dodd-Frank Act's Section 1502 in the US, requiring companies to audit their supply chains for conflict minerals. The situation has partially improved with certification schemes, but remains a concern.
How was tantalum discovered?
Tantalum was discovered in 1802 by Swedish chemist Anders Gustav Ekeberg in mineral samples from Scandinavia and Finland. He named it tantalum after Tantalus from Greek mythology: who was cursed to stand in water that receded when he tried to drink it: because the metal was 'tantalized' by acids it would not react with. For decades tantalum was confused with niobium, and the two were not definitively separated until 1866.
Why is tantalum so corrosion-resistant?
Tantalum, like titanium and zirconium, forms a thin, dense, adherent oxide film (Ta2O5) when exposed to oxygen. This passive film is chemically inert and self-healing. Tantalum resists attack by all mineral acids except hydrofluoric acid and hot concentrated alkalis, making it suitable for chemical reactor linings, heat exchangers in the chemical industry, and medical implants where long-term stability in body fluids is essential.