Niobium (Nb)

Niobium is a shiny, ductile transition metal used in high-strength low-alloy steels, superconducting magnets, and corrosion-resistant alloys. It was first identified in 1801 by Charles Hatchett, who named it columbium; the name niobium became official in 1950.

Atomic Number
41
Atomic Mass
92.906
Phase (STP)
Solid
Block
D
Electronegativity (Pauling)
1.6

Bohr Atomic Model

Protons
41
Neutrons
52
Electrons
41
Identity
Atomic Number41
SymbolNb
NameNiobium
Group5
Period5
Position
Period5
Group Label5
Grid X5
Grid Y5
Physical Properties
Atomic Mass (u)92.906
Density (g/cm³)8.57
Melting Point (K)2750 K 2477 °C
Boiling Point5014 K 4744 °C
Phase at STPSolid
CategoryTransition Metals
Liquid Density (g/cm³)
Molar Volume (cm³/mol)10.84
Emission Spectrum (nm)
Discovery
English NameNiobium
English Pronunciationnaɪˈoʊbiəm
Latin NameNiobium
Latin Pronunciationnee-OH-bee-um
Year1801
DiscovererCharles Hatchett
CountryEngland
CAS Number7440-03-1
CID Number23936
RTECS Number
Atomic Properties
Electron ShellK2 L8 M18 N12 O1
Electron Configuration[Kr] 4d^45s^1
Oxidation States-1 +2 +3 +4 +5
Ion ChargeNb⁵⁺
Ionization Potential (eV)6.759
Electronegativity (Pauling)1.6
Electron Affinity (kJ/mol)88.381
Electrons41
Protons41
Neutrons52
ValenceV
BlockD
Atomic Radius (pm)146
Covalent Radius (pm)156
van der Waals Radius (pm)218
Thermodynamic Properties
PhaseSOLID
Heat of Fusion (kJ/mol)26.8
Specific Heat (J/g·K)0.265
Thermal Expansion (1/K)0
Heat of Vaporization (kJ/mol)690
Mechanical Properties
Brinell Hardness736
Mohs Hardness6
Vickers Hardness1320
Bulk Modulus (GPa)170
Young's Modulus (GPa)105
Shear Modulus (GPa)38
Poisson Ratio0.4
Sound Speed (m/s)3480
Refractive Index
Thermal Conductivity (W/m·K)53
Electromagnetic Properties
Electrical Conductivity (S/m)6700000
Electrical TypeCONDUCTOR
Magnetic TypePARAMAGNETIC
Volume Magnetic Susceptibility
Mass Magnetic Susceptibility
Molar Magnetic Susceptibility
Resistivity (Ω·m)0
Superconducting Point (K)9.25
Crystal Properties
StructureBody-centered cubic (bcc)
SystemCUBIC
Space GroupIm−3m
a (Å)3.3
b (Å)3.3
c (Å)3.3
α (°)90
β (°)90
γ (°)90
Debye Temperature (K)275
Nuclear Properties
RadioactiveNo
Half-life
Lifetime
Neutron Cross-section (barn)1.15
Safety Information
Health Hazard
Reactivity Hazard
Specific HazardFine powder may be flammable; bulk metal is generally stable.
Prevalence
Universe
Sun
Oceans
Human Body
Earth Crust0.002
Meteorites