Tantalum
transition metalProperties
| Property | Value |
|---|---|
| Atomic Mass | 180.95 amu |
| Category | transition metal |
| Group | 5 |
| Period | 6 |
| Electron Configuration | [Xe] 4f14 5d3 6s2 |
| Electronegativity | 1.5 (Pauling) |
| Oxidation States | 5 |
| Melting Point | 3290 K (3016.8 °C) |
| Boiling Point | 5731 K (5457.9 °C) |
| Density | 16.69 g/cm³ |
| Discovered By | Anders Gustaf Ekeberg (1802) |
About Tantalum
Tantalum got its name from Tantalus, the mythological figure who couldn't drink the water around him — Ekeberg picked it because the metal stubbornly refuses to dissolve in acid. That refusal is the whole engineering story. A passive Ta₂O₅ film a few nanometers thick shrugs off aqua regia, hot HCl, hot HNO₃, and just about anything short of HF or hot oleum. The same oxide is what makes tantalum capacitors work: anodize a sintered tantalum powder pellet and you get an extraordinarily thin, defect-free dielectric, which is why a 100 µF Ta cap can be smaller than a grain of rice. Ta is also one of the few metals you can leave inside a body indefinitely — bone grows directly onto the oxide surface, so it shows up in cranial plates, dental posts, and porous orthopedic scaffolds. Most of it comes out of coltan, the same ore that gave the supply chain its conflict-minerals problem.
Fun Fact
A solid-tantalum capacitor packs more capacitance per volume than almost any other dielectric option because the anodic Ta₂O₅ film on a sintered powder slug is only nanometers thick and almost defect-free. The trade-off is that they fail short — a stressed Ta cap can sometimes ignite, which is why most safety-critical designs derate them to 50% of rated voltage.
Common Uses
- Sintered-anode electrolytic capacitors in phones, hearing aids, and pacemakers
- Cranial plates, dental implants, and porous bone-ingrowth orthopedic scaffolds
- Reactor liners and heat exchangers for hot HCl and bromine service
- Ni-based superalloy additive in single-crystal turbine blades for grain stability
- TaN diffusion-barrier sputtering targets between copper and silicon in chip fabrication
- Carbide tooling (TaC) for cutting nickel and titanium superalloys