Quick Facts
| Property | Value |
|---|---|
| Symbol | Nb |
| Atomic Number | 41 |
| Atomic Mass | 92.906 u |
| Category | Transition Metal |
| Period | 5 |
| Group | 5 |
| Block | d |
| Electron Configuration | [Kr] 4d⁴ 5s¹ |
Physical Properties
| Property | Value |
|---|---|
| State at 20°C | Solid |
| Density | 8.57 g/cm³ |
| Melting Point | 2477°C (2750 K) |
| Boiling Point | 4744°C (5017 K) |
| Appearance | Gray metallic, blue when oxidized |
Atomic Properties
| Property | Value |
|---|---|
| Electron Configuration | [Kr] 4d⁴ 5s¹ |
| Electronegativity | 1.6 (Pauling scale) |
| First Ionization Energy | 652.1 kJ/mol |
| Atomic Radius | 146 pm |
| Covalent Radius | 164 pm |
| Van der Waals Radius | 207 pm |
History and Discovery
Discovered by: Charles Hatchett Year of Discovery: 1801 Location: London, England
Etymology
Named after Niobe, daughter of Tantalus in Greek mythology, because niobium is found with tantalum and is similar to it (just as Niobe was daughter of Tantalus).
Discovery Story
Charles Hatchett discovered niobium in 1801 analyzing a mineral sample from Connecticut. He named it columbium. For decades, chemists debated whether columbium and tantalum were the same element. In 1864, Christian Wilhelm Blomstrand confirmed they were different. IUPAC officially adopted "niobium" in 1950, though "columbium" is still used in US industry.
Isotopes
| Isotope | Natural Abundance | Half-life | Decay Mode |
|---|---|---|---|
| ⁹³Nb | 100% | Stable | - |
Occurrence
Natural Abundance
Niobium is moderately rare, comprising about 20 ppm of Earth's crust. It is found in columbite ((Fe,Mn)(Nb,Ta)₂O₆) and pyrochlore. Brazil produces about 90% of the world's niobium.
Extraction and Production
- Aluminothermic Reduction: Of niobium oxide
- Sources: Primarily pyrochlore in Brazil
- Separation: From tantalum by solvent extraction
- Global production: about 70,000 tons annually
Applications and Uses
Steel Industry
- High-strength low-alloy (HSLA) steels (main use)
- Pipeline steels
- Automotive steels
- Structural steels
Superalloys
- Jet engine components
- Rocket nozzles
- Gas turbines
- Heat-resistant equipment
Superconductors
- Niobium-titanium (MRI magnets, particle accelerators)
- Niobium-tin (high-field magnets)
- Superconducting radio-frequency cavities
Other Uses
- Jewelry (anodized niobium)
- Capacitors
- Surgical implants
- Commemorative coins
Biological Role
Niobium has no known biological role and is not essential for any organism.
In the Human Body
Niobium is not normally found in the body. It has low toxicity.
Medical Uses
Niobium alloys are used in some medical implants due to their biocompatibility.
Safety and Hazards
Toxicity
Niobium has very low toxicity. Most niobium compounds are considered safe.
Handling Precautions
- Niobium powder can be flammable
- Dust may irritate skin and eyes
- Standard metal handling procedures apply
- Generally considered safe to handle
Environmental Impact
Niobium mining is concentrated in Brazil with typical mining environmental impacts. The metal itself is non-toxic.
Interesting Facts
- Brazil dominates global niobium production (about 90%)
- Niobium was called "columbium" in the US for over 150 years
- Anodized niobium produces beautiful iridescent colors
- Niobium-titanium superconductors are used in MRI machines
- A small amount of niobium greatly increases steel strength