Template:Infobox niobium

Niobium,  ₄₁Nb

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General properties
Pronunciation	Template:Infobox element/pronunciation
Appearance	gray metallic, bluish when oxidized
Standard atomic weight (Ar, standard)	Template:Infobox element/standard atomic weight
Mass number	Template:Infobox element/symbol-to-most-stable-isotope (most stable isotope)
Niobium in the periodic table
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Atomic number (Z)	41
Group	Template:Infobox element/group
Period	period 5
Block	d-block
Element category	Template:Infobox element/category format
Electron configuration	[Kr] 4d4 5s1
Electrons per shell	2, 8, 18, 12, 1
Physical properties
Phase at STP	solid
Melting point	2750 K ​(2477 °C, ​4491 °F)
Boiling point	5017 K ​(4744 °C, ​8571 °F)
Density (near r.t.)	8.57 g/cm3
Heat of fusion	30 kJ/mol
[[Enthalpy of vaporization|Heat of Template:Engvar]]	689.9 kJ/mol
Molar heat capacity	24.60 J/(mol·K)
[[Vapor pressure|Template:Engvar pressure]] Template:Infobox element/vapor pressure table
Atomic properties
Oxidation states	Template:Infobox element/symbol-to-oxidation-state
Electronegativity	Pauling scale: 1.6
[[Ionization energy|Template:Engvar energies]]	1st: 652.1 kJ/mol 2nd: 1380 kJ/mol 3rd: 2416 kJ/mol
Atomic radius	empirical: 146 pm
Covalent radius	164±6 pm
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Other properties
Crystal structure	​Template:Infobox element/crystal structure Template:Infobox element/crystal structure
Speed of sound thin rod	3480 m/s (at 20 °C)
Thermal expansion	7.3 µm/(m·K)
Thermal conductivity	53.7 W/(m·K)
Electrical resistivity	152 nΩ·m (at 0 °C)
Magnetic ordering	paramagnetic
Young's modulus	105 GPa
Shear modulus	38 GPa
Bulk modulus	170 GPa
Poisson ratio	0.40
Mohs hardness	6.0
Vickers hardness	870–1320 MPa
Brinell hardness	735–2450 MPa
CAS Number	7440-03-1
History
Naming	after Niobe in Greek mythology, daughter of Tantalus (tantalum)
Discovery	Charles Hatchett (1801)
First isolation	Christian Wilhelm Blomstrand (1864)
Recognized as a distinct element by	Heinrich Rose (1844)
Main isotopes of niobium
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