Niobium is a shiny grey, ductile metal that takes on a bluish tinge when exposed to air at room temperature for extended periods. Niobium's chemical properties are almost identical to the chemical properties of tantalum, which appears below niobium in the periodic table.
When it is processed at even moderate temperatures niobium must be placed in a protective atmosphere. The metal begins to oxidize in air at 200 °: C and its oxidation states are +2, +3, +5.
Niobium has a number of uses: it is a component of some stainless steels and an alloy of other nonferrous metals. These alloys are strong and are often used in pipeline construction. Other uses;
The metal has a low capture cross-section for thermal neutrons and so finds use in the nuclear industries.
It is also the metal used in arc welding[?] rods for some stabilized grades of stainless steel.
Because of its bluish color, niobium is also used in body piercingjewelry (usually as an alloy).
Appreciable amounts of niobium in the form of high-purity ferroniobium and nickel niobium are used in nickel-, cobalt-, and iron-base superalloys for such applications as jet engine components, rocket subassemblies, and heat-resisting and combustion equipment. For example, advanced air frame systems such as those used in the Gemini program used this metal.
Niobium is being evaluated as an alternative to tantalum in capacitors.
It also has superconductive properties that make it suitable for making superconductive magnets such as one made form Nb-Zr wire. This supermagnet retains its superconductive properties in strong magnetic fields which researchers hope will suit it for use in direct large-scale generation of electric power.
Niobium (Greek mythology: Niobe, daughter of Tantalus) was discovered by Charles Hatchett in 1801. Hatchett found niobium in columbite ore that was sent to England in the 1750s by John Winthrop who was the first governor of Connecticut. There was a considerable amount of confusion about the difference between the closely-related niobium and tantalum that wasn't resolved until 1846 by Heinrich Rose[?] and Charles Marignac[?] who rediscovered the element. Since Rose was unaware of Hatchett's work he gave the element a different name, niobium. In 1864Christian Blomstrand[?] was the first to prepare the metal. He did this by reducing niobium chloride by heating it in a hydrogen atmosphere.
Columbium was the name originally given to this element by Hatchet but the International Union of Pure and Applied Chemistry (IUPAC) officially adopted "niobium" as the name for element 41 in 1950 after 100 years of controversy. Many leading chemical societies and government organizations refer to it by the official IUPAC name but most leading metallurgists, metal societies, and most leading American commercial producers still refer to the metal by the original "columbium."
Naturally occurring niobium is composed of one stable isotope (Nb-93). The most stable radioisotopes are Nb-92 with a half life of 34.7 million years, Nb-94 (half life: 20300 years), and Nb-91 with a half life of 680 years. There is also a meta state at 0.031 mega electron volts whose half life is 16.13 years. Twenty three other radioisotopes have been characterized. Most of these have half lives that are less than two hours except Nb-95 (35 days), Nb-96 (23.4 hours) and Nb-90 (14.6 hours). The primary decay mode before the stable Nb-93 is electron capture and the primary mode after is beta emission with some neutron emission[?] occurring in the first mode of the two mode decay of Nb-104, 109 and 110.
Niobium containing compounds are relatively rarely encountered by most people but many are highly toxic and should be treated with care. Metallic niobium dust is an eye and skin irritant and also can be a fire hazard. Niobium has no biological role.
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