Niobium

Not to be confused with nihonium.

Niobium, 41Nb
A lump of gray shining crystals with hexagonal facetting
Niobium
Pronunciation/naɪˈoʊbiəm/ ​(ny-OH-bee-əm)
AppearanceGray metallic, bluish when oxidized
Standard atomic weight Ar°(Nb)
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
Groupgroup 5
Periodperiod 5
Block  d-block
Electron configuration[Kr] 4d4 5s1
Electrons per shell2, 8, 18, 12, 1
Physical properties
Phase at STPsolid
Melting point2750 K ​(2477 °C, ​4491 °F)
Boiling point5017 K ​(4744 °C, ​8571 °F)
Density (at 20° C)8.582 g/cm3[3]
Heat of fusion30 kJ/mol
Heat of vaporization689.9 kJ/mol
Molar heat capacity24.60 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 statescommon: +5
−3,? −1,[4] 0,? +1,? +2,[4] +3,[4] +4[4]
ElectronegativityPauling scale: 1.6
Ionization energies
  • 1st: 652.1 kJ/mol
  • 2nd: 1380 kJ/mol
  • 3rd: 2416 kJ/mol
Atomic radiusempirical: 146 pm
Covalent radius164±6 pm
Color lines in a spectral range
Spectral lines of niobium
Other properties
Natural occurrenceprimordial
Crystal structure ​body-centered cubic (bcc) (cI2)
Lattice constant
Cubic body-centered crystal structure for niobium
a = 330.05 pm (at 20 °C)[3]
Thermal expansion7.07×10−6/K (at 20 °C)[3]
Thermal conductivity53.7 W/(m⋅K)
Electrical resistivity152 nΩ⋅m (at 0 °C)
Magnetic orderingparamagnetic
Young's modulus105 GPa
Shear modulus38 GPa
Bulk modulus170 GPa
Speed of sound thin rod3480 m/s (at 20 °C)
Poisson ratio0.40
Mohs hardness6.0
Vickers hardness870–1320 MPa
Brinell hardness735–2450 MPa
CAS Number7440-03-1
History
Namingafter Niobe in Greek mythology, daughter of Tantalus (tantalum)
DiscoveryCharles Hatchett (1801)
First isolationChristian Wilhelm Blomstrand (1864)
Recognized as a distinct element byHeinrich Rose (1844)
Isotopes of niobium
Main isotopes[5] Decay
abun­dance half-life (t1/2) mode pro­duct
91Nb synth 680 y β+ 91Zr
91mNb synth 60.86 d IT 91Nb
β+ 91Zr
92Nb trace 3.47×107 y β+ 92Zr
93Nb 100% stable
93mNb synth 16.12 y IT 93Nb
94Nb trace 2.04×104 y β− 94Mo
95Nb synth 34.991 d β− 95Mo
 Category: Niobium
| references

Niobium is a chemical element; it has symbol Nb (formerly columbium, Cb) and atomic number 41. It is a light grey, crystalline, and ductile transition metal. Pure niobium has a Mohs hardness rating similar to pure titanium,[6] and it has similar ductility to iron. Niobium oxidizes in Earth's atmosphere very slowly, hence its application in jewelry as a hypoallergenic alternative to nickel. Niobium is often found in the minerals pyrochlore and columbite. Its name comes from Greek mythology: Niobe, daughter of Tantalus, the namesake of tantalum. The name reflects the great similarity between the two elements in their physical and chemical properties, which makes them difficult to distinguish.[7]

English chemist Charles Hatchett reported a new element similar to tantalum in 1801 and named it columbium. In 1809, English chemist William Hyde Wollaston wrongly concluded that tantalum and columbium were identical. German chemist Heinrich Rose determined in 1846 that tantalum ores contain a second element, which he named niobium. In 1864 and 1865, a series of scientific findings clarified that niobium and columbium were the same element (as distinguished from tantalum), and for a century both names were used interchangeably. Niobium was officially adopted as the name of the element in 1949, but the name columbium remains in current use in metallurgy in the United States.

It was not until the early 20th century that niobium was first used commercially. Niobium is an important addition to high-strength low-alloy steels. Brazil is the leading producer of niobium and ferroniobium, an alloy of 60–70% niobium with iron. Niobium is used mostly in alloys, the largest part in special steel such as that used in gas pipelines. Although these alloys contain a maximum of 0.1%, the small percentage of niobium enhances the strength of the steel by scavenging carbide and nitride. The temperature stability of niobium-containing superalloys is important for its use in jet and rocket engines.

Niobium is used in various superconducting materials. These alloys, also containing titanium and tin, are widely used in the superconducting magnets of MRI scanners. Other applications of niobium include welding, nuclear industries, electronics, optics, numismatics, and jewelry. In the last two applications, the low toxicity and iridescence produced by anodization are highly desired properties. Niobium is considered a technology-critical element.

  1. ^ "Standard Atomic Weights: Niobium". CIAAW. 2017.
  2. ^ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (4 May 2022). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
  3. ^ a b c Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. ISBN 978-1-62708-155-9.
  4. ^ a b c d Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 28. ISBN 978-0-08-037941-8.
  5. ^ Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
  6. ^ Samsonov, G. V. (1968). "Mechanical Properties of the Elements". In G.V. Samsonov (ed.). Handbook of the Physicochemical Properties of the Elements. New York, US: IFI-Plenum. pp. 387–446. doi:10.1007/978-1-4684-6066-7_7. ISBN 978-1-4684-6066-7. Archived from the original on 2 April 2015.
  7. ^ Knapp, Brian (2002). Francium to Polonium. Atlantic Europe Publishing Company, p. 40. ISBN 0717256774.