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NOBIUM Niobium, also known as columbium, is a chemical element with the symbol Nb (formerly Cb) and atomic number 41. Niobium is a light grey, crystalline, and ductile transition metal. Pure niobium has a Mohs hardness rating similar to that of pure titanium,[2] and it has similar ductility to iron. Niobium oxidizes in the 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, hence the former name "columbium". Its name comes from Greek mythology, specifically Niobe, who was the daughter of Tantalus, the namesake of tantalum. The name reflects the great similarity between the two elements in their physical and chemical properties, making them difficult to distinguish.[3]

Niobium, 41Nb A lump of gray shining crystals with hexagonal facetting Niobium Pronunciation /naɪˈoʊbiəm/ ​(ny-OH-bee-əm) Appearance gray metallic, bluish when oxidized Standard atomic weight Ar, std(Nb) 92.90637(1)[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 Element category

 Transition metal

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, +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 Color lines in a spectral range Spectral lines of niobium Other properties Natural occurrence primordial Crystal structure ​body-centered cubic (bcc)Cubic body-centered crystal structure for niobium 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 Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct 90Nb syn 15 h β+ 90Zr 91Nb syn 680 y ε 91Zr 91mNb syn 61 d IT 91Nb 92Nb trace 3.47×107 y ε 92Zr γ – 92m1Nb syn 10 d 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 Category Category: Niobium viewtalkedit | references The English chemist Charles Hatchett reported a new element similar to tantalum in 1801 and named it columbium. In 1809, the English chemist William Hyde Wollaston wrongly concluded that tantalum and columbium were identical. The 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. 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. 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 superconducting 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.