Niobium

Niobium, umwhile columbium, is a chemical element wi the seembol Nb (umwhile Cb) an atomic nummer 41. It is a saft, grey, ductile transeetion metal, whilk is aften foond in the pyrochlore mineral, the main commercial soorce for niobium, an columbite. The name comes frae Greek meethology: Niobe, dauchter o Tantalus.

Niobium, ₄₁Nb

Niobium
Pronunciation	/naɪˈoʊbiəm/ ​(ny-OH-bee-əm)
Appearance	gray metallic, bluish when oxidized
Standard atomic weight Ar, std(Nb)	7001929063700000000♠92.90637(1)
Niobium in the periodic cairt
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Airn Cobalt Nickel Capper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Siller (element) Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gowd Mercur (element) Thallium Leid (element) Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Ununtrium Flerovium Ununpentium Livermorium Ununseptium Ununoctium V ↑ Nb ↓ Ta zirconium ← niobium → molybdenum
Atomic nummer (Z)	41
Group	group 5
Period	period 5
Block	d-block
Element category	Transeetion metal
Electron confeeguration	[Kr] 4d4 5s1
Electrons per shell	2, 8, 18, 12, 1
Pheesical properties
Phase at STP	solid
Meltin pynt	2750 K ​(2477 °C, ​4491 °F)
Bylin pynt	5017 K ​(4744 °C, ​8571 °F)
Density (near r.t.)	8.57 g/cm3
Heat o fusion	30 kJ/mol
Heat o vapourisation	689.9 kJ/mol
Molar heat capacity	24.60 J/(mol·K)
Vapour pressur P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 2942 3207 3524 3910 4393 5013
Atomic properties
Oxidation states	−3, −1, +1, +2, +3, +4, +5 (a mildly acidic oxide)
Electronegativity	Pauling scale: 1.6
Ionisation energies	1st: 652.1 kJ/mol 2nd: 1380 kJ/mol 3rd: 2416 kJ/mol
Atomic radius	empirical: 146 pm
Covalent radius	164±6 pm
Colour lines in a spectral range Spectral lines o niobium
Ither properties
Naitural occurrence	primordial
Creestal structur	​cubic bouk-centred [[File:cubic bouk-centred|frameless|alt=Cubic bouk-centred creestal structur for niobium|upright=0.23|Cubic bouk-centred creestal structur for niobium]]
Speed o soond 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 orderin	paramagnetic
Young's modulus	105 GPa
Shear modulus	38 GPa
Bulk modulus	170 GPa
Poisson ratio	0.40
Mohs haurdness	6.0
Vickers haurdness	870–1320 MPa
Brinell haurdness	735–2450 MPa
CAS Nummer	7440-03-1
History
Namin	after Niobe in Greek meethologie, dochter o Tantalus (tantalum)
Diskivery	Charles Hatchett (1801)
First isolation	Christian Wilhelm Blomstrand (1864)
Recognised as a distinct element bi	Heinrich Rose (1844)
Main isotopes o niobium
Iso­tope Abun­dance Hauf-life (t1/2) Decay mode Pro­duct 90Nb syn 15 h β+ 90Zr 91Nb syn 680 y ε 91Zr 91mNb syn 61 d IT 91Nb 92m1Nb syn 10 d ε 92Zr γ – 92Nb trace 3.47×107 y ε 92Zr γ – 93Nb 100% stable 93mNb syn 16 y IT 93Nb 94Nb trace 20.3×103 y β− 94Mo γ – 95Nb syn 35 d β− 95Mo γ – 95mNb syn 4 d IT 95Nb 96Nb syn 24 h β− 96Mo