About

Niobium is a light gray, crystalline, and ductile transition metal. It is used in various superalloys to increase strength, especially those needing heat resistance for applications like jet engines and rockets. Niobium-based alloys are also important type-II superconductors, used to create the powerful magnets in MRI scanners and particle accelerators.

Atomic Properties

Atomic Number41

Atomic Weight92.906 u

Neutrons (common)52

Electron Configuration[Kr] 4d⁴ 5s¹

Full Configuration1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d⁴ 5s¹

Electrons per Shell2, 8, 18, 12, 1

Electronegativity1.6

Electron Affinity86.1 kJ/mol

Oxidation States+5, +4, +3, +2, -1

Covalent Radius137 pm

Ionic Radius64 pm

Periodic Table Position

Group5

Period5

BlockD

Chemical SeriesTransition metals

Physical Properties

State at STPsolid

Appearanceshiny grey metallic, bluish when oxidized

Crystal Structurebcc

Magnetic Orderingparamagnetic

Speed of Sound3,480 m/s

Poisson Ratio0.4

Thermal Properties

Melting Point2,750 K

Boiling Point5,017 K

Thermal Expansion0 1/K

Thermal Conductivity53.7 W/(m·K)

Specific Heat0.265 J/(g·K)

Molar Heat24.6 J/(mol·K)

Heat of Fusion26.8 kJ/mol

Heat of Vaporization689.9 kJ/mol

Abundance

In Earth's Crust20 ppm

In Ocean0 ppm

In Solar System0.002 ppm

In Human Body0.021 ppm

In Universe0.002 ppm

Discovery

Discovered byCharles Hatchett

Discovery Year1,801

Occurrenceprimordial

CAS Number7440-03-1

Electron Configuration

Energy

↿⇂

↿

Isotopes of Niobium

Symbol ▲	Mass (u) ▲	Abundance ▲	Half-life ▲	Decay Mode ▲
⁹¹Nb	90.906996	—	680 y	Electron Capture, Positron Emission
⁹²Nb	91.907190	—	34.7 My	Electron Capture
⁹³Nb	92.906380	100%	Stable	Stable

Interactive Visualization

Explore the 3D Bohr model of Niobium in our interactive viewer.

View 3D Model of Niobium