Tungsten is the chemical element with atomic number 74, symbol W (from
German Wolfram). Its name in French comes from the Swedish tung ("heavy") and
sten ("stone") and therefore means "heavy stone".
Tungsten is found in many minerals such as wolframite and scheelite. The simple
tungsten body is a very hard and heavy gray-white steel transition metal. In its
pure form, it is mainly used in electrical applications (filaments of
incandescent lamps), but in the form of compounds or alloys, it has many
applications, such as the production of tools requiring high hardness.
Tungsten has 35 known isotopes, with a mass number varying between 158 and 192,
as well as 11 nuclear isomers. Among these isotopes, four are stable, 182W,
183W, 184W and 186W, and they constitute with 180W, a very long-lived
radioisotope (half-life of 1.8 ¡Á 1018 years), all of natural tungsten, in
proportions varying from 14 to 30% (0.12% for 180W). Like all elements heavier
than zirconium, tungsten is theoretically unstable, and all of its stable
isotopes are suspected of being weakly radioactive, disintegrating by ¦Á emission
into isotopes of the corresponding hafnium. Tungsten is assigned a standard
atomic mass of 183.84 (1) u.
magnesium bismuth manganese chromium cobalt titanium
Tungsten vanadium niobium indium molybdenum antimony
rhenium germanium zirconium cadmium hafnium
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