Niobium

Niobium, ₄₁Nb

Niobium
Pronunciation	/naɪˈoʊbiəm/ (listenⓘ) ​(ny-OH-bee-əm)
Appearance	Gray metallic, bluish when oxidized
Standard atomic weight Ar°(Nb)
	92.90637(1)
Niobium in the periodic table
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 Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver 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 Gold Mercury (element) Thallium Lead 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 Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson V ↑ Nb ↓ Ta zirconium ← niobium → molybdenum
Atomic number (Z)	41
Group	group 5
Period	period 5
Block	d-block
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
Heat of vaporization	689.9 kJ/mol
Molar heat capacity	24.60 J/(mol·K)
Vapor pressure 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, 0, +1, +2, +3, +4, +5 (a mildly acidic oxide)
Electronegativity	Pauling scale: 1.6
Ionization energies	1st: 652.1 kJ/mol 2nd: 1380 kJ/mol 3rd: 2416 kJ/mol
Atomic radius	empirical: 146 pm
Covalent radius	164±6 pm
Spectral lines of niobium
Other properties
Natural occurrence	primordial
Crystal structure	​body-centered cubic (bcc)
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)
Isotopes of niobium v e
Main isotopes Decay abun­dance half-life (t1/2) mode pro­duct 91Nb synth 680 y ε 91Zr 92Nb trace 3.47×107 y β+ 92Zr 93Nb 100% stable 93mNb synth 16.12 y IT 93Nb 94Nb trace 20.4×103 y β− 94Mo 95Nb synth 34.991 d β− 95Mo
Category: Niobium view talk edit | references

Niobium is a chemical element. It is sometimes named columbium. It has the chemical symbol Nb. It has the atomic number 41. It is a rare metal. Niobium is hard and grey. It is ductile. In chemistry it is placed in a group of metal elements named the transition metals. Niobium was discovered in a variety of a mineral called columbite (now called niobite). Niobite is an ore of niobium.

Niobium is considered a technology-critical element. It is used in alloys, such as to make special steels and strong welded joints. Less than 0.1% of Niobium significantly improves the strength of steel. It is in the superconducting alloys used in MRI scanners, which are one of the most important medical inventions of the modern age.

Name and history

In 1801, Charles Hatchett claimed to have discovered a new chemical element in a sample from the United States. He named the mineral "columbite" and his element "columbium", after Columbia, another name for the United States. However, chemists were uncertain that columbium was a new element because of its similarity to tantalum. William Hyde Wollaston claimed that columbium and tantalum were the same element. Other chemists claimed that up to five new elements were in these minerals, one of which was named "niobium".

It took until 1864 to make pure tantalum and niobium and show there were only two elements in these minerals. One of these two elements was named "tantalum", but this showed that "niobium" and "columbium" were the same element. Americans preferred the name "columbium", while "niobium" was more common in Europe. Almost a hundred years later, IUPAC decided on the name niobium as part of an effort to make the names of chemical elements more universal.

Production

Niobium and tantalum are in the same group, so their chemistry is very similar. Their ores make a solid solution series called coltan. Niobium and tantalum are both extracted from coltan by leaching. Pyrochlore is another important niobium ore, which can be reduced by aluminium or carbon to make ferroniobium..

References

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