Niobium
Definition and meaning of Niobium in chemistry.
Niobium is a light gray, crystalline, and ductile transition metal with the chemical symbol Nb and an atomic number of 41. It is often found in the minerals pyrochlore and columbite, sharing very similar physical and chemical properties with the heavier element tantalum.
In more detail
Positioned in group 5 and period 5 of the periodic table, niobium is a refractory metal known for its remarkable ability to enhance the strength of alloys, especially at low temperatures. It exhibits a body-centered cubic crystalline structure and becomes a superconductor at cryogenic temperatures, particularly when alloyed with titanium or tin for use in superconducting magnets. Niobium reacts with nonmetals like carbon, nitrogen, and oxygen at high temperatures, but forms an extremely stable and passive oxide layer at room temperature that protects it from corrosion by most aggressive acids. In nature, it is inextricably linked with tantalum in geological deposits, and the two are notoriously challenging to separate chemically due to their almost identical atomic radii resulting from the lanthanide contraction. Its oxidation states range from -1 to +5, with the +5 state being the most common and stable, forming compounds like niobium pentoxide which is crucial for manufacturing optical glasses.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Nb |
| Atomic number | 41 |
| Atomic mass | 92.906 u |
| Category | Transition Metal |
| State at room temperature | Solid |
| Melting point | 2477 °C |
| Boiling point | 4744 °C |
| Year discovered | 1801 |
Niobium is alloyed with steel in minute quantities to construct high-strength, low-alloy structural steel used extensively in modern automobile bodies, bridges, and high-pressure gas pipelines.
Frequently asked questions
Why was niobium formerly called columbium?
It was originally named columbium by its discoverer, Charles Hatchett, after the mineral columbite, but the name niobium was officially adopted by IUPAC in 1949.
Is niobium used in jewelry?
Yes, niobium is hypoallergenic and can be anodized to display a wide array of vibrant colors without the use of dyes, making it popular for body piercing jewelry.