tungsten (tung'st?n) [Swed.,=heavy stone], metallic chemical element; symbol W; at. no. 74; at. wt. 183.85; m.p. about 3,410°C; b.p. 5,660°C; sp. gr. 19.3 at 20°C; valence +2, +3, +4, +5, or +6. Tungsten is a very hard, silver-white to steel-gray metal with a body-centered cubic crystalline structure. In its chemical properties it resembles molybdenum, the element above it in Group 6 of the periodic table. It is sometimes called wolfram, and the chemical symbol is taken from this name; in naming compounds of tungsten, use of the name wolfram as a root is preferred. Tungsten is one of the most dense metals and has a higher melting point than any other metal.

Pure tungsten is ductile, and wires made of it, even those of very small diameter, have a very high tensile strength. The element is resistant to ordinary acids and aqua regia but dissolves in a mixture of hydrofluoric and nitric acids. It forms compounds with carbon, chlorine, oxygen, sulfur, and some other elements. It is hexavalent in its most important compounds. It forms tungstic acid (H2WO4), or wolframic acid, which is the basis of a series of salts called tungstates, or wolframates. Tungsten metal is used extensively for filaments for light bulbs and electronic tubes. Carboloy, stellite, and Tungsten Rods are of importance in industry because they retain their hardness and strength at high temperatures.
Tungsten is usually added to steel in the form of ferrotungsten, obtained by the reduction of ferrous tungstate in an electric furnace. Tungsten carbide is used in place of diamond for dies and as an abrasive. Sodium wolframate is used in the fireproofing of fabrics, in the weighting of silk, and as a mordant in dyeing. Tungsten does not occur uncombined in nature; large deposits of its ores are found in various parts of the world. The trioxide occurs in nature as the mineral wolfram ochre; scheelite and wolframite are the chief wolframate minerals.Tungsten Powder is usually prepared from the trioxide by reduction with hydrogen or carbon. Tungsten was first isolated from tungstic acid in 1783 by the de Elhuyar brothers.

Tungsten (pronounced /'t??st?n/), also known as wolfram (/'w?lfr?m/, WOOL-fr?m), is a chemical element with the chemical 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. Also remarkable is its very high density of 19.3 times heavier than water, and 71% heavier than lead. Tungsten is often brittle and hard to work in its raw state; if pure, it can be cut with a hacksaw.

The pure form is used mainly in electrical applications, but its many compounds and alloys have many applications, most notably in incandescent light bulb filaments, X-ray tubes (as both the filament and target), and superalloys.

Tungsten Carbide Powder is the only metal from the third transition series that is known to occur in biomolecules, and is the heaviest element known to be used by living organisms.
In 1781, Carl Wilhelm Scheele discovered that a new acid, tungstic acid, could be made from scheelite (at the time named tungstenite). Scheele and Torbern Bergman suggested that it might be possible to obtain a new metal by reducing this acid.[8] In 1783, José 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.

In World War II, tungsten played a significant role in background political dealings. Portugal, as the main European source of the element, was put under pressure from both sides, because of its deposits of wolframite ore. Tungsten's resistance to high temperatures and its strength in alloys made it an important raw material for the weaponry industry.

from:answers

As a bit of a health nut, I've kept quiet about something I didn't start consuming regularly until moving to Portland, Ore., aka Beervana. Yes, that something is beer. That bastion of bad health. The oh-so-tasty temptress. The barren wasteland of big bellies.

Or maybe beer has gotten a worse reputation than it deserves. In recent years, researchers have extolled several healthy side effects of beer (in moderation, of course), from its role in limiting kidney stones and gallstones to lowering the risk of adult-onset diabetes and even, due to its folate content, helping prevent cancer.

And that's not all. Silicon, present to varying degrees in various beers, has been linked to higher bone-mineral density in animals--including, of course, in humans. So researchers at the University of California at Davis set out to analyze 100 commercial beers to determine silicon content. They report their findings this week in the Journal of the Science of Food and Agriculture.

The average beer contains 29.4 parts per million (ppm), with my personal favorite--India Pale Ales (this is very validating)--topping the list at a whopping 41.2 ppm. Ales in general average 32.8 ppm, and my least favorite, lagers, were down around 20. Hey, maybe my body actually knows what kind of beer to drink!

"The wine guys have stolen the moral high ground," said Charles Bamforth, a biochemist and professor of food science at UC Davis who also goes by the title Anheuser-Busch Endowed Professor. He adds:

    The reality is there's now growing consensus around the world that the active ingredient in alcoholic beverages that counters atherosclerosis is alcohol. It doesn't matter if it's wine or beer. I resent the stance that people take that wine is better. It's not.

Bamforth's team's findings suggest that raw ingredients and brewing techniques determine how much silicon is in the final pour. They found that malt, a sprouted grain, is the greatest source of Polycrystalline Silicon ; starches in sprouted barley or wheat break down into sugars that yeast converts into alcohol. (Barley contains even more silicon than wheat.)

The jury is still out on how much silicon is best. Katherine Tucker, a nutritional epidemiologist at Northeastern University in Boston, says people tend to consume an average of between 20 mg and 50 mg of silicon a day, and studies suggest that people should get at least 46. Depending on the kind of beer being consumed, you can get about that much in two or three beers. Besides beer, Polycrystalline Silicon sources include fruit, vegetables, and whole grains, news I took singing "la la la" with my hands over my ears.

Apparently the average guy--who nutritionists generally agree should stop at two drinks a day--gets most of his silicon through beer; the average lady--who they say should stop at one--through grains and veggies. Since I am a lover of grains, veggies, and beer alike, I shall henceforth be called Silicon Wonder Woman. After all, I can control my wireless mouse on my beer-happy (or is it hoppy?) abs.

from:news.cnet

The report is devoted to investigation of current standing of market of tungsten in CIS countries and forecast of the market development. The report consists of 7 Sections, contains 132 pages, including 31 Figures, 54 Tables and Appendix. This work is desk study. As information sources, we used data of Rosstat, Inter-state Committee on Statistics of CIS countries, Federal Customs Service of Russia, official domestic railage statistic of JSC RZhD (former Ministry of Railway Transport of Russia), sectoral (industrial) and regional press, annual and quarterly reports of companies, as well as data from web-sites of company-producers and consumers of tungsten.

The first Section of the report presents brief characteristics of standing of world market of Tungsten Bar (reserves, production, prices).
The second Section is devoted to description of mineral resources base of tungsten in the CIS.
The third Section is devoted to analysis of production, export, import and consumption of tungsten concentrate in CIS countries. The Section presents in details technology of production of tungsten concentrate, as well as description of the main company-producers of tungsten concentrate in CIS countries.
The fourth Section is devoted to description of production, export and import of tungsten-containing products in the CIS. The Section presents data on production of ferrotungsten, of tungsten anhydride and ammonia paratungstate, tungsten metal, tungsten carbide and hard alloys, as well as description of the main company-producers of the products.

The fifth Section presents analysis of consumption of Tungsten Rod , including supply-demand balance of the product, dynamics and pattern of the consumption of tungsten metal in Russia, as well as brief characteristics of end-uses.
The sixth Section is devoted to projects and investments in tungsten industry in CIS countries (projects on development and resuming mining of tungsten in CIS countries are presented here).
The seventh Section of the report presents current standing and forecast of production and consumption of tungsten in the CIS up to 2010
The Appendix includes addresses and contact information on the main company-producers of tungsten products in CIS countries

According to the analysis of authoritative industry experts,The global supply of tungsten mainly consists of two parts,Part of the new supply of tungsten are concentrate production,This part of the total supply of tungsten accounted for 76%,Another part of the final tungsten product from the waste material,accounted for 24%,According to nationwide survey of Tungsten Industry by China Tungsten Industry Association in 2004,our country’s utilization of waste tungsten is very low,Only 10% of tungsten supply,in the advanced countries, utilization of waste tungsten are generally above 30%,generally speaking,The cost of recycling waste tungsten are lower than the tungsten ore smelting processing costs,But requires greater investment and stronger environmental protection technical support.

In china the develop of economy is the first,Although many intellectuals have loudly called for protection of the environment,but in China,Every day a large number of industrial wastes, wastewater is discharged out of,Serious pollute our environment for survival,This is why China’s low rate of utilization of waste recycling tungsten,How can the economic development and environmental protection be better coordinated,Now it still seems a very difficult problem,Because up to now still not a very good program proposed.

Sincerely wish that,in the near further,the develop of china economic keep on growing,meanwhile the environment will be better,we can see the blue sky and white cloud, we can hear the birdies singing in the sky.

Ferro molybdenum is an important iron molybdenum alloy, with a molybdenum content of 60-70%  It is the main source for molybdenum alloying of HSLA steel. The molybdenum is mined and is subsequently transformed into the molybdenum(VI) oxide MoO3. This oxide is mixed with iron oxide and aluminium and is reduced in the an aluminothermic reaction to molybdenum and iron. The ferromolybdenum can be purified by electron beam melting or used as it is. For alloying with steel the ferromolybdenum is added to molten steel before casting. Among the biggest suppliers of Ferro molybdenum in Europe is the German trading house Grondmet in Düsseldorf, Germany.

Molybdenum (pronounced /?m?l?b'di?n?m/ mol-ib-DEE-n?m, from Neo-Latin Molybdaenum, from Ancient Greek Μ?λυβδος molybdos, meaning lead), is a Group 6 chemical element with the symbol Mo and atomic number 42. The free element, which is a silvery metal, has the sixth-highest melting point of any element. It readily forms hard, stable carbides, and for this reason it is often used in high-strength steel alloys. Molybdenum does not occur as the free metal in nature, but rather in various oxidation states in minerals. Industrially, molybdenum compounds are used in high pressure and high temperature applications, as pigments and catalysts.

Molybdenum minerals have long been known, but the element was "discovered" (in the sense of differentiating it as a new entity from minerals salts of other metals) in 1778 by Carl Wilhelm Scheele. The metal was first isolated in 1781 by Peter Jacob Hjelm.

Most molybdenum compounds have low water solubility, but the molybdate ion MoO2−4 is soluble and will form if molybdenum-containing minerals are in contact with oxygen and water. Recent theories suggest that the release of oxygen by early life was important in removing molybdenum from minerals into a soluble form in the early oceans, where it was used as a catalyst by single-celled organisms. This sequence may have been important in the history of life, because molybdenum-containing enzymes then became the most important catalysts used by some bacteria to break into atoms the atmospheric molecular nitrogen, allowing biological nitrogen fixation. This, in turn allowed biologically driven nitrogen-fertilization of the oceans, and thus the development of more complex organisms.

At least 50 molybdenum-containing enzymes are now known in bacteria and animals, though only the bacterial and cyanobacterial enzymes are involved in nitrogen fixation. Due to the diverse functions of the remainder of the enzymes, molybdenum is a required element for life in higher organisms (eukaryotes), though not in all bacteria.

In its pure form, Molybdenum Powder is silvery white metal with a Mohs hardness of 5.5. It has a melting point of 2,623 °C (4,753 °F); of the naturally occurring elements, only tantalum, osmium, rhenium, tungsten and carbon have higher melting points. Molybdenum burns only at temperatures above 600 °C (1,112 °F).[4] It has one of the lowest coefficient of thermal expansion among commercially used metals. Tensile strength of molybdenum wires increases about 3 times from about 10 to 30 GPa when their diameter decreases from ~50–100 nm to 10 nm.

There are 35 known isotopes of molybdenum ranging in atomic mass from 83 to 117, as well as four metastable nuclear isomers. Seven isotopes occur naturally, with atomic masses of 92, 94, 95, 96, 97, 98 and 100. Of these naturally occurring isotopes, only molybdenum-92 and molybdenum-100 are unstable. All unstable isotopes of molybdenum decay into isotopes of niobium, technetium and ruthenium.

Molybdenum-98 is the most abundant isotope, comprising 24.14% of all molybdenum. Molybdenum-100 has a half-life of about 1019 y and undergoes double beta decay into ruthenium-100. Molybdenum isotopes with mass numbers from 111 to 117 all have half-lives of approximately 150 ns.

As also noted below, the most common isotopic molybdenum application involves molybdenum-99, which is a fission product. It is a parent radioisotope to the short-lived gamma-emitting daughter radioisotope technetium-99m, a nuclear isomer which is used in various imaging applications in medicine.

from:wiki

A ballistic vest, bulletproof vest or bullet-resistant vest is an item of personal armor that helps absorb the impact from firearm-fired projectiles and shrapnel from explosions, and is worn on the torso. Soft vests are made from many layers of woven or laminated fibers and can be capable of protecting the wearer from small caliber handgun and shotgun projectiles, and small fragments from explosives such as hand grenades.

Metal or ceramic plates can be used with a soft vest, providing additional protection from rifle rounds, and metallic components or tightly-woven fiber layers can give soft armor resistance to stab and slash attacks from a knife. Soft vests are commonly worn by police forces, private citizens and private security guards or bodyguards, whereas hard-plate reinforced vests are mainly worn by combat soldiers, police tactical units and hostage rescue teams.

Modern body armor may combine a ballistic vest with other items of protective clothing, such as a combat helmet . Vests intended for police and military use may also include ballistic shoulder and side protection armor components, and bomb disposal officers wear heavy armor and helmets with face visors and spine protection.
Ballistic vests use layers of very strong fiber to "catch" and deform a bullet, mushrooming it into a dish shape, and spreading its force over a larger portion of the vest fiber. The vest absorbs the energy from the deforming bullet, bringing it to a stop before it can completely penetrate the textile matrix. Some layers may be penetrated but as the bullet deforms, the energy is absorbed by a larger and larger fiber area.

While a vest can prevent bullet penetration, the vest and wearer still absorb the bullet's energy. Even without penetration, modern pistol bullets contain enough energy to cause blunt force trauma under the impact point. Vest specifications will typically include both penetration resistance requirements and limits on the amount of impact energy that is delivered to the body.

Vests designed for bullets offer little protection against blows from sharp implements, such as knives, arrows or ice picks, or from bullets manufactured of non-deformable materials, i.e. those containing a steel core instead of lead. This is because the impact force of these objects stays concentrated to a relatively small area, allowing them to puncture the fiber layers of most bullet-resistant fabrics.

Textile vests may be augmented with metal (steel or titanium), ceramic or polyethylene plates that provide extra protection to vital areas. These hard armor plates have proven effective against all handgun bullets and a range of rifles. These upgraded ballistic vests have become standard in military use, as soft body armor vests are ineffective against military rifle rounds. Corrections officers and other law enforcement officers often wear vests which are designed specifically against bladed weapons and sharp objects. These vests may incorporate coated and laminated para-aramid textiles or metallic components.

Due to the various different types of projectile, it is often inaccurate to refer to a particular product as "bulletproof" because this implies that it will protect against any and all threats. Instead, the term bullet resistant is generally preferred.

Body armor standards are regional. Around the world ammunition varies and as a result the armor testing must reflect the threats found locally. Law enforcement statistics show that many shootings where officers are injured or killed involve the officer's weapon. As a result each law enforcement agency or para-military organizations will have their own standard for armor performance if only to ensure that their armor protects them from their own weapon. While many standards exist a few standards are widely used as models. The US National Institute of Justice ballistic and stab documents are examples of broadly accepted standards. In addition to the NIJ, the UK Home Office Scientific Development Branch (HOSDB - formerly the Police Scientific Development Branch (PSDB)) standards are used by a number of other countries and organizations. These "model" standards are usually adapted by other counties by incorporation of the basic test methodologies with modification of the bullets that are required for test. NIJ Standard-0101.06 has specific performance standards for bullet resistant vests used by law enforcement.

from:wiki

The most important use of the molybdenum in living organisms is as a metal heteroatom at the active site in certain enzymes. In nitrogen fixation in certain bacteria, the nitrogenase enzyme, which is involved in the terminal step of reducing molecular nitrogen, usually contains molybdenum in the active site (though replacement of Mo with iron or vanadium is also known). The structure of the catalytic center of the enzyme is similar to that in iron-sulfur proteins, it incorporates a Fe4S3 and MoFe3S3 clusters.

In 2008, evidence was reported that a scarcity of molybdenum in the Earth's early oceans was a limiting factor in the further evolution of eukaryotic life (which includes all plants and animals) as eukaryotes cannot fix nitrogen and must acquire it from prokaryotic bacteria. The scarcity of molybdenum resulted from the relative lack of oxygen in the early ocean. Oxygen dissolved in seawater helps dissolve molybdenum from minerals on the sea bottom. However, although oxygen may promote nitrogen fixation via making molybdenum available in water, it also directly poisons these nitrogenase enzymes, so that organisms which continued to fix nitrogen in aerobic conditions were required to isolate their nitrogen-fixing enzymes in heterocysts, or similar structures.

Though molybdenum forms compounds with various organic molecules, including carbohydrates and amino acids, it is transported throughout the human body as MoO2−4. At least 50 molybdenum-containing enzymes were known by 2002, mostly in bacteria, and their number is increasing with every year; those enzymes include aldehyde oxidase, sulfite oxidase and xanthine oxidase. In some animals, and in humans, the oxidation of xanthine to uric acid, a process of purine catabolism, is catalyzed by xanthine oxidase, a molybdenum-containing enzyme. The activity of xanthine oxidase is directly proportional to the amount of molybdenum in the body. However, an extremely high concentration of molybdenum reverses the trend and can act as an inhibitor in both purine catabolism and other processes. Molybdenum concentrations also affect protein synthesis, metabolism and growth.

In animals and plants these enzymes use molybdenum bound at the active site in a tricyclic molybdenum cofactor. All molybdenum-using enzymes so far identified in nature use this cofactor, save for the phylogenetically ancient nitrogenases, which fix nitrogen in some bacteria and cyanobacteria. Molybdenum enzymes in plants and animals catalyze the oxidation and sometimes reduction of certain small molecules, as part of the regulation of nitrogen, sulfur and carbon cycles.

Molybdenum Powder and fumes, as can be generated by mining or metalworking, can be toxic, especially if ingested (including dust trapped in the sinuses and later swallowed). Low levels of prolonged exposure can cause irritation to the eyes and skin. Direct inhalation or ingestion of molybdenum and its oxides should be avoided.  OSHA regulations specify the maximum permissible molybdenum exposure in an 8-hour day as 5 mg/m3. Chronic exposure to 60 to 600 mg/m3 can cause symptoms including fatigue, headaches and joint pains.

from:wiki

The ability of molybdenum to withstand extreme temperatures without significantly expanding or softening makes it useful in applications that involve intense heat, including the manufacture of aircraft parts, electrical contacts, industrial motors and filaments. Molybdenum is also used in alloys for its high corrosion resistance and weldability. Molybdenum contributes corrosion resistance to type 316 stainless steel by lattice strain, increasing the energy required to dissolve out iron atoms from the surface. Most high-strength steel alloys contain 0.25% to 8% molybdenum. Despite such small portions, more than 43,000 tonnes of molybdenum are used as an alloying agent each year in stainless steels, tool steels, cast irons and high-temperature superalloys.

Because of its lower density and more stable price, Molybdenum powder is used instead of Tungsten Powder . An example is the 'M' series of high-speed steels such as M2, M4 and M42 as substitution for the 'T' steel series. Molybdenum can be implemented both as an alloying agent and as a flame-resistant coating for other metals. Although its melting point is 2,623 °C (4,753 °F), molybdenum rapidly oxidizes at temperatures above 760 °C (1,400 °F) making it better-suited for use in vacuum environments.

Other molybdenum based alloys have only limited applications. Because of the corrosion resistance against molten zinc, molybdenum and the molybdenum tungsten alloy (70%/30%) are used for piping, stirrers and pump impellers which come into contact with molten zinc.

Molybdenum-99 is a parent radioisotope to the daughter radioisotope technetium-99m, which is used in many medical procedures.

Molybdenum disulfide (MoS2) is used as a solid lubricant and a high-pressure high-temperature (HPHT) antiwear agent. It forms strong films on metallic surfaces and is a common additive to HPHT greases—in case of a catastrophic grease failure, thin layer of molybdenum prevents contact of the lubricated parts. Molybdenum disilicide (MoSi2) is an electrically conducting ceramic with primary use in heating elements operating at temperatures above 1500 °C in air.

Molybdenum trioxide (MoO3) is used as an adhesive between enamels and metals. Lead molybdate (wulfenite) co-precipitated with lead chromate and lead sulfate is a bright-orange pigment used with ceramics and plastics.

Molybdenum powder is used as a fertilizer for some plants, such as cauliflower. It is also used in NO, NO2, NOx analyzers in power plants for pollution controls. At 350 °C (662 °F) the element acts as a catalyst for NO2/NOx to form only NO molecules for consistent readings by infrared light. Ammonium heptamolybdate is used in biological staining procedures.

from:wiki

A recent scandal has erupted in that gold bars are in fact tungsten gold and sold to India via the IMF, says Gold Basics:

    It looks that a big part of Gold bars in Banks vaults are in fact Tungsten Bar plated gold , the scandal is just starting to leak and it could cause the burst of the Gold bubble , if the general public starts losing faith in the gold not being able to spot the real from the fake cause it wouldn't be too difficult to make convincing fake gold bars out of gold-plated tungsten (which costs $30 a pound compared to $12,000 a pound for gold).

Bad Credit Advisor gives an update:

    Probably the only way to discover a fake without scratching your bar or coin or without performing some chemical analysis, is to drop suspicious gold object against a solid hardwood desk, as long as you do not mind having some nicks and small dents on it. Dropping a real gold coin will produce a very particular ringing sound quite different from the one that tungsten counterfeit coin makes.

    Before you panic and start dropping your gold, understand that tungsten is the metal which is extremely difficult to work with. Besides being brittle, it has the highest known melting point of any non alloyed metal at 3,422°C or almost 6,192°F. So such counterfeit gold requires quite a bit of investment and knowledge, which both of course are available our there. So it is important to buy your gold bullion from reputable dealers, but even they can make a mistake and unknowingly sell you something else.

Safe Haven has a good piece on how to tell the difference from gold and tungsten bars:

    As far as the properties of Tungsten Rod versus gold, they are similar. But there are important differences, per the Ron Paul blog at dailypaul.com. In coins, there is a difference in the ring. The speed of sound thru tungsten is different from that with gold (as is detectible with a cheap ultrasound scanner). Tungsten is very hard and brittle (with a higher melting point) while gold is soft and pliable (on a hardness scale, it is alleged that talc at 1 means gold at 2.5, tungsten at 7.5 and diamonds at 10.0).

    The atomic weight of gold is said to be 196.96 versus 183.86 for tungsten. Gold allegedly has a specific gravity of 19.32 and tungsten of 19.25. Precision measuring and weighing devices (which are now available all over the world) could measure a bar and easily calculate its exact volume and weight for either gold or for tungsten. These devices would immediately detect tungsten bars in contrast to gold bars.

from:beforeitsnews

In single crystal silicon, the crystalline framework is homogenous, which can be recognized by an even external coloring. In single crystal silicon, also called monocrystal, the crystal lattice of the entire sample is continuous and unbroken with no grain boundaries. Large single crystals are exceedingly rare in nature and can also be difficult to produce in the laboratory (see also recrystallisation). In contrast an amorphous structure where the atomic position is limited to short range order.

Polycrystalline and paracrystalline phases (see Polycrystal) are composed of a number of smaller crystals or crystallites. Polycrystalline silicon (or semicrystalline silicon, polysilicon, poly-Si, or simply "poly") is a material consisting of multiple small silicon crystals. Polycrystalline cells can be recognized by a visible grain, a “metal flake effect”. Semiconductor grade (also solar grade) polycrystalline silicon is converted to "single crystal" silicon - meaning that the randomly associated crystallites of silicon in "polycrystalline silicon" are converted to a large "single" crystal. Single crystal silicon is used to manufacture most Si-based microelectronic devices. Polycrystalline silicon can be as much as 99.9999% pure.[citation needed] Ultra-pure poly is used in the semiconductor industry, starting from poly rods that are five to eight feet in length. In microelectronic industry (semiconductor industry), poly is used both at the macro-scale and micro-scale (component) level. Processes by which single crystals are grown (see Czochralski process, Bridgman technique, Float-zone silicon).

Mitsubishi Electric Corporation announced on February 2009 that it has improved its world's highest conversion efficiency rate for a 150 x 150 millimeter practical-size multi-crystalline silicon photovoltaic (PV) cell by 0.3 points from 18.6% to achieve a new world record of 18.9%.

Polycrystalline silicon is also a key component of solar panel construction. Growth of the photovoltaic solar industry is limited by the supply of the polysilicon material.For the first time, in 2006, over half of the world's supply of polysilicon is being used for production of renewable electricity solar power panels.[4] Only twelve factories are known to produce solar-grade polysilicon in 2008. Monocrystalline silicon is higher priced and more efficient than multicrystalline.

Tungsten, at atomic number 74, is the heaviest element known to be used by any living organism, with the next heaviest being iodine (Z = 53). Tungsten has not been found to be necessary or used in eukaryotes, but it is an essential nutrient for some bacteria. For example, enzymes called oxidoreductases use tungsten similarly to molybdenum by using it in a tungsten-pterin complex with molybdopterin.

Molybdopterin, despite its name, does not contain molybdenum, but may complex with either molybdenum or Tungsten Bar in use by living organisms. Tungsten-using enzymes reduce free carboxylic acids to aldehydes. The first tungsten-requiring enzyme to be discovered also requires selenium, and in this case the tungsten-selenium pair may function analogously to the molybdenum-sulfur pairing of some molybdenum cofactor requiring enzymes. One of the enzymes in the oxidoreductase family which sometimes employ tungsten (bacterial formate dehydrogenate H) is known to use a selenium-molybdenum version of molybdopterin.Although a tungsten-containing xanthine dehydrogenase from bacteria has been found to contain tungsten-molydopterin and also non-protein bound selenium, a Tungsten Bar molybdopterin complex has not been definitively described.

Tungsten, also known as wolfram , is a chemical element with the chemical 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 tungsten bar form is used mainly in electrical applications, but its many compounds and alloys are used in many applications, most notably in incandescent 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 is known to occur in biomolecules, and is the heaviest element known to be used by living organisms.