41
Nb
Niobium
92.90637
Niobium (Nb)
Transition MetalGroup 5Period 5d-block-block
Niobium, formerly columbium, is a chemical element with symbol Nb (formerly Cb) and atomic number 41. It is a soft, grey, ductile transition metal, which is often found in the pyrochlore mineral, the main commercial source for niobium, and columbite. The name comes from Greek mythology:Niobe, daughter of Tantalus since it is so similar to tantalum.
Latin name: Niobium
Atomic Number
41
Atomic Mass
92.90637 g/mol
Phase (STP)
Solid
Electron Config.
[Kr] 4d⁴ 5s¹
General
SymbolNb
Atomic Number41
Atomic Mass92.90637 g/mol
CategoryTransition Metal
Group5
Period5
Blockd-block
Electron Configuration[Kr] 4d⁴ 5s¹
Valence Electrons5
Colourgray metallic
Appearancegray metallic, bluish when oxidized
CAS NumberCAS7440-03-1
Physical Properties
Phase (STP)Solid
Density8.57 g/cm³
Melting Point2476.85°C · 4490.33°F · 2750.00 K
Boiling Point4743.85°C · 8570.93°F · 5017.00 K
Atomic Properties
Atomic Radius198 pm
Electronegativity1.6 Pauling
Ionization Energy652 kJ/mol
Oxidation States+5, +4, +3, +2
Ion ChargeNb3+/Nb5+
Thermodynamic
Molar Heat24.6 J/(mol·K)
Crystal Structure
Crystal Structurebody-centered cubic
Mechanical Properties
Mohs Hardness6
Abundance
In Earth's Crust0.0020%
Discovery & History
Discovery Year1801
Discovered ByCharles Hatchett
Country of DiscoveryEngland
Isotopes of Niobium
| Isotope | Abundance | Half-life | Decay |
|---|---|---|---|
| Nb-93 | 100% | Stable | — |
| Nb-94 | — | 2.03 × 10⁴ years | β⁻ |