Niobium is so similar to the metallic tantalum that the two were mistakenly thought to be the same element for nearly 40 years. The mineral columbite is the main source of this lustrous metal. Niobium does not occur naturally in its pure state. When mined, it has many applications. As the element is not dangerous in the human body, it is used in implants, such as pacemakers. Niobium also does not expand on impact, which is why it is used to make parts for space rockets.
Resumen de propiedades (Nb)
| Atomic weight | 92.90637(1) |
| Discoverer (year) | Hatchet, Charles (1801) |
| Natural form | metallic solid (body centered cubic) |
| Electron configuration | [Kr] 4d4 5s1 |
| Melting point (ºC) | 2468 |
| Boiling point (ºC) | 4927 |
| Abundance in earth's crust (ppm) | 20 |
| Isotope (abundance) | 93Nb (100) |
| Density g/cm3 | 8.57 |
| Van der Waals radius (pm) | 218 |
| Covalent radius (pm) | 156 |
| Electronegativity (Pauling) | 1.6 |
| Vaporization enthalpy (kJ/mol) | 696.60 |
| Enthalpy of fusion (kJ/mol) | 30.00 |
| Specific heat capacity (J/g·K) at 25ºC and 1 atm | 0.27 |
| Thermal conductivity (W/cm·K) at 25ºC and 1 atm | 0.540 |
| Oxidation state | +5, +3 |
| Electron affinity (eV) | 0.92 |
| 1st Ionization potential (eV) | 6.7589 |
