Tungsten

Tungsten chemical element is symbolized by the Latin symbol W, means tungsten heavy stone, discovered by Swedish chemist Carl Schell in 1871, a very important element, and is used in the manufacture of wire in incandescent light bulbs.

In the form of tungsten ore, is a metal, steel gray, which are often fragile and difficult to work, but if pure, can be done easily. Is an act of fraud by or withdrawal. Of all pure metals in their form, tungsten has the highest melting point (3422 ° C 0.6192 ° F), and lowest vapor pressure (at temperatures above 1650 ° C, 3000 degrees F) and higher tensile strength. Tungsten has a lower coefficient of thermal expansion of any pure metal. Thermal expansion and low melting point and high strength of tungsten is due to the strong covalent bonds between atoms consist of electrons of the tungsten 5D. Alloying small quantities of tungsten with steel greatly increases its strength.


 * Elecrons**

History
In 1781, Carl Wilhelm Scheele discovered that a new acid, tungstic acid, could be made from scheelite(at the time named tungsten). Scheele suggested that it might be possible to obtain a new metal by reducing this acid.In 1783, Jose and Fausto Elhuyar found an acid made from wolframite that was identical to tungstic acid. Later that year, in Spain, the brothers succeeded in isolating tungsten by reduction of this acid with charcoal, and they are credited with the discovery of the element.

Symbol- W Atomic number- 74. Atomic weight- 183.84. Element category: transition metal.

The name is different from its symbol because the w comes from its Latin name of Wolfram. Tungsten is found in some types of light bulbs. Image from:[|Google Images - Chemicool]

Tungsten is the heaviest known element that is biologically functional. It's density is 19.3 times the density of water. It's main use is for electrical applications. Tungsten has a boiling point of 5660.0 °C. Tungsten has a melting point of 3410.0 °C.

Platinum-Like Behavior of Tungsten Carbide in Surface Catalysis

__[|+] __Author Affiliations
 * 1)   [|R. B. Levy]  and
 * 2)   [|M. Boudart]
 * 1)  Stauffer Laboratories of Chemistry and Chemical Engineering, Stanford University, Stanford, California 94305

ABSTRACT
Tungsten carbide catalyzes the formation of water from hydrogen and oxygen at room temperature, the reduction of tungsten trioxide by hydrogen in the presence of water, and the isomerization of 2,2-dimethylpropane to 2-methylbutane. This catalytic behavior, which is typical of platinum, is not exhibited at all by tungsten. The surface electronic properties of the latter are therefore modified by carbon in such a way that they resemble those of platinum.

Harmful effects: Tungsten is considered to be of low toxicity. Characteristics: Tungsten is a very hard, dense, silvery-white, lustrous metal that tarnishes in air, forming a protective oxide coating. In powder form tungsten is gray in color. The metal has the highest melting point of all metals, and at temperatures over 1650 oC also has the highest tensile strength. Pure tungsten is ductile, and tungsten wires, even of a very small diameter, have a very high tensile strength. Tungsten is highly resistant to corrosion. It forms tungstic acid (H 2 WO 4 ), or wolframic acid from the hydrated oxide (WO3) and its salts are called tungstates, or wolframates. Tungsten is one of the five major refractory metals (metals with very high resistance to heat and wear). The other refractory metals are [|molybdenum], [|tantalum], [|rhenium] and [|niobium].

Uses of Tungsten
Tungsten and its alloys are widely used for filaments in older style (not energy saving) electric bulbs and electronic tubes. It is used for making heavy metal alloys because of its hardness. Tungsten is used for high-temperature applications such as welding. High speed steel (which can cut material at higher speeds than carbon steel), contains up to 18% tungsten. Tungsten carbide (WC or W 2 C) is extremely hard and is used to make drills. It is also used for jewelry because of its hardness and wear resistance.
 * useful for glass-to-metal seals since the thermal expansion is about the same as borosilicate glass
 * tungsten and its alloys are used extensively for filaments for electric lamps, electron and television tubes, and for metal evaporation work
 * electrical contact points for car distributors
 * X-ray targets
 * windings and heating elements for electrical furnaces
 * missile and high-temperature applications
 * high-speed tool steels and many other alloys contain tungsten
 * the carbide is important to the metal-working, mining, and petroleum industries
 * calcium and magnesium tungstates are widely used in fluorescent lighting
 * tungsten salts are used in the chemical and tanning industries
 * tungsten disulphide is a dry, high-temperature lubricant, stable to 500°C
 * tungsten bronzes and other tungsten compounds are used in paints
 * TV tubes (electron tubes)
 * X-ray targets
 * Symbol:** W **Atomic Number:** 74 **Atomic Mass:** 183.84 amu **Melting Point:** 3410.0 °C (3683.15 K, 6170.0 °F) **Boiling Point:** 5660.0 °C (5933.15 K, 10220.0 °F) **Number of Protons/Electrons:** 74 **Number of Neutrons:** 110 **Classification:** Transition Metal **Crystal Structure:** Cubic **Density @ 293 K:** 19.3 g/cm3 **Color:** Silver

Atomic Structure

 * [[image:http://www.chemicalelements.com/bohr/b0074.gif width="355" height="353"]] ||  || **Number of Energy Levels:** 6
 * First Energy Level:** **Second Energy Level:** **Third Energy Level:** **Fourth Energy Level:** **Fifth Energy Level:** **Sixth Energy Level:** ||

Isotopes

 * ** Isotope ** || ** Half Life ** ||
 * W-180 || Stable ||
 * W-181 || 121.2 days ||
 * W-182 || Stable ||
 * W-183 || Stable ||
 * W-184 || Stable ||
 * W-185 || 74.8 days ||
 * W-185m || 1.6 minutes ||
 * W-186 || Stable ||
 * W-187 || 23.9 hours ||
 * W-188 || 69.4 days ||

Facts
An example of where one could find tungsten would be in wolframite or naturally within Earth.
 * Date of Discovery:** 1783 **Discoverer:** Fausto and Juan Jose de Elhuyar **Name Origin:** From the Swedish words //tung sten// (heavy stone) **Symbol Origin:** From //wolfram// (its German name) **Uses:** used widely in electronics industry **Obtained From:** scheelite, wolframite

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