NIOBIUM
- Atomic Number: 41
- Atomic Symbol: Nb
- Atomic Weight: 92.9064
- Electron Configuration: -18-12-1
History:
-
(Niobe, daughter of Tantalus) Discovered in 1801 by Hatchett in an
ore sent to England more than a century before by John Winthrop the
Younger, first governor of Connecticut. The metal was first prepared
in 1864 by Blomstrand, who reduced the chloride by heating it in a
hydrogen atmosphere. The name niobium was adopted by the
International Union of Pur and Applied Chemicstry in 1950 after 100
years of controversy. Many leading chemical societies and government
organizations refer to it by this name. Most metallurgists, leading
metal societies, and all but one of the leading U.S. commercial
producers, however, still refer to the metal as "columbium." The
element is found in niobite (or columbite), niobite-tantalite,
parochlore, and euxenite. Large deposits of niobum have been found
associated with carbonatites (carbon-silicate rocks), as a constituent
of parochlore. Extensive ore reserves are found in Canada, Brazil,
Nigeria, Zaire, and in Russia. The metal can be isolated from
tantalum, and prepared in several ways. It is a shiny, white, soft,
and ductile metal, and takes on a bluish cast when exposed to air at
room temperatures for a long time. The metal starts to oxidize in
air at 200C, and when processed at even moderate temperatures must be
placed in a protective atmosphere. It is used in arc-welding rods for
stabilized grades of stainless steel. Thousands of poinds of niobium
have beeen used in advanced air frame systems such as were used in the
Gemini space program. The element has superconductive properties;
superconductive magnets have been made with Nb-Zr wire, which retains
its superconductivity in strong magnetic fields. This type of
application offers hope of direct large-scale generation of electric
power. Eighteen isotopes of niobium are known. Niobium metal (99.5%
pure) is priced at about $75/lb.
Source: CRC Handbook of Chemistry and Physics, 1913-1995. David R. Lide, Editor in Chief. Author: C.R. Hammond
Copyright ©1995-1998
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