Everything about Tungsten totally explained
|-
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182W || 26.50% || colspan="4" | W is
stable with 108
neutrons
|-
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183W || 14.31% || colspan="4" | W is
stable with 109
neutrons
|-
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184W || 30.64% || colspan="4" | W is
stable with 110
neutrons
|-
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186W || 28.43% || colspan="4" | W is
stable with 112
neutrons
Tungsten, also known as
wolfram(/ˈwʊlfrəm/), is a
chemical element that has the symbol
W and
atomic number 74.
A steel-gray
metal, tungsten is found in several
ores, including
wolframite and
scheelite. It is remarkable for its robust physical properties, especially the fact that it has the highest
melting point of all the non-
alloyed metals and the second highest of all the elements after
carbon. Tungsten is often
brittle and hard to
work in its raw state; however, if pure, it can be cut with a
hacksaw. The pure form is used mainly in electrical applications, but its many compounds and alloys are used in many applications, most notably in
light bulb filaments,
X-ray tubes (as both the filament and target), and
superalloys. Tungsten is also the only metal from the third transition series that's known to occur in
biomolecules.
Etymology
"Tungsten" (from the
Swedish tung sten, meaning "heavy stone") is commonly accepted as the name of the material, although some chemists (primarily in
Germany but also for example in
Sweden) refer to it as "wolfram", from its ore
wolframite. The name "wolframite" was derived from "
volf rahm", the word
Johan Gottschalk Wallerius used to refer to it in 1747. This, in turn, was translated from "
Lupi spuma", the word
Georg Agricola used to refer to the element in 1546. Its English translation is "wolf's froth", so named because the mineral consumed a large amount of
tin in its extraction. Its chemical symbol,
W, is derived from wolfram as well. Tungsten has the lowest
coefficient of thermal expansion of any pure metal. Alloying small quantities of tungsten with
steel greatly increases its toughness.
182W,
T1/2 > 8.3·10
18 yr;
183W,
T1/2 > 29·10
18 yr;
184W,
T1/2 > 13·10
18 yr;
186W,
T1/2 > 27·10
18 yr.
On average, two alpha decays of
180W occur in one gram of natural tungsten per year.
27 artificial
radioisotopes of tungsten have been characterized, the most stable of which are
181W with a
half-life of 121.2 days,
185W with a half-life of 75.1 days,
188W with a half-life of 69.4 days and
178W with a half-life of 21.6 days. All of the remaining
radioactive isotopes have half-lives of less than 24 hours, and most of these have half-lives that are less than 8 minutes. Tungsten also has 4
meta states, the most stable being
179mW (t
½ 6.4 minutes).
Chemical properties
Tungsten resists attack by
oxygen,
acids, and
alkalis.
Compounds
» Main article:
The most common formal
oxidation state of tungsten is +6, but it exhibits all oxidation states from -1 to +6. Sixteen recent cases of
cancer in children were discovered in the Fallon area, which has now been identified as a
cancer cluster (however, the majority of the cancer victims are not longtime residents of Fallon). Dr. Carol H. Rubin, a branch chief at the CDC, said data demonstrating a link between tungsten and leukemia isn't available at present.
Applications
Because of its ability to produce hardness at high temperatures and its high
melting point (the second highest of any known element), tungsten is used in many high-temperature applications. These include
light bulb,
cathode-ray tube, and
vacuum tube filaments, as well as
heating elements and nozzles on
rocket engines.
In metal alloys,
high speed steel contains tungsten; some tungsten steels contain as much as 18% tungsten.
Superalloys containing tungsten are used in
turbine blades and wear resistant parts and coatings. Examples are
Hastelloy and
Stellite.
Tungsten powder is used as a filler material in
plastic composites, which are used as a nontoxic substitute for
lead in
bullets, shot, and radiation shields.
Since this element's thermal expansion is similar to
borosilicate glass, it's used for making glass-to-metal seals.
Production
Tungsten is found in the
minerals
wolframite (
iron-
manganese tungstate, FeW
O4/MnWO
4),
scheelite (
calcium tungstate, (CaWO
4),
ferberite and
hübnerite. There are major deposits of these minerals in
China (with about 57% world share),
Russia,
Austria and
Portugal, reports the
British Geological Survey. Approximately 75% of the world's tungsten resources are thought to exist in
China, It can be used in that state or converted into solid bars.
Tungsten can also be extracted by hydrogen reduction of WF
6 (WF
6 + 3h
2 = W + 6HF) or
pyrolytic decomposition (WF
6 + energy = W + 3f
2).
In World War II, tungsten played an enormous role in background political dealings.
Portugal, as the main European source of the element, was put under pressure from both sides, because of its sources of wolframite ore. The resistance to high temperatures, as well as the extreme strength of its alloys, made the metal into a very important raw material for the weaponry industry.
Further Information
Get more info on 'Tungsten'.
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