Technical data for Niobium

Overview
NameNiobium
SymbolNb
Atomic Number41
Atomic Weight92.90638
Density8.57 g/cm3
Melting Point2477 °C
Boiling Point4744 °C

Thermal properties
PhaseSolid
Melting Point2477 °C
Boiling Point4744 °C
Absolute Melting Point2750 K
Absolute Boiling Point5017 K
Heat of Fusion26.8 kJ/mol
Heat of Vaporization690 kJ/mol
Heat of CombustionN/A
Specific Heat265 J/(kg K)[note]
Thermal Conductivity54 W/(m K)
Thermal Expansion7.3×10-6 K-1

Bulk physical properties
Density8.57 g/cm3
Density (Liquid)N/A
Molar Volume0.000010841
Brinell Hardness736 MPa
Mohs Hardness6 MPa
Vickers Hardness1320 MPa
Bulk Modulus170 GPa
Shear Modulus38 GPa
Young Modulus105 GPa
Poisson Ratio0.4
Speed of Sound3480 m/s
Thermal Conductivity54 W/(m K)
Thermal Expansion7.3×10-6 K-1

Reactivity
Valence5
Electronegativity1.6
ElectronAffinity86.1 kJ/mol
Ionization Energies
652.1, 1380, 2416, 3.7×103, 4877, 9847, 1.21×104 kJ/mol

Health and Safety
Autoignition PointN/A
FlashpointN/A

Classifications
Alternate NamesNone
Nams of AllotropesNone
Blockd
Group5
Period5
Electron Configuration[Kr]4d45s1
ColorGray
Discovery
1801 in United Kingdom
Gas phaseN/A
CAS NumberCAS7440-03-1

Electrical properties
Electrical TypeConductor
Electrical Conductivity6.7×106 S/m
Resistivity1.5×10-7 m Ω
Superconducting Point9.25

Magnetic properties
Magnetic TypeN/A
Curie PointN/A
Mass Magnetic Susceptibility2.81×10-8
Molar Magnetic Susceptibility2.611×10-9
Volume Magnetic Susceptibility0.0002408

Abundances
% in Universe2×10-7%
% in Sun4×10-7%
% in Meteorites0.000019%
% in Earth's Crust0.0017%
% in Oceans1×10-10%
% in HumansN/A

Atomic dimensions and structure
Atomic Radius198 pm
Covalent Radius137 pm
Van der Waals RadiusN/A
Crystal StructureBody Centered Cubic
Lattice Angles
π/2, π/2, π/2
Lattice Constants
330.04, 330.04, 330.04 pm
Space Group NameIm_ 3m
Space Group Number229

Nuclear Properties
Half-LifeStable
LifetimeStable
Stable Isotopes
93Nb
Isotopic Abundances
93Nb100%

Notes on the properties of Niobium:
Specific Heat: Value given for solid phase.