Tungsten - wikipedia Tungsten This article is about the chemical element. For other uses, see Tungsten ( disambiguation ). Tungsten, W General properties Pronunciation / ˈtʌŋstən / ​ ( TUNG - stən ) Alternative name wolfram, pronounced : / ˈwʊlfrəm / ( WUUL - frəm ) Appearance grayish white, lustrous Standard atomic weight ( A ) 7002183840000000000 ♠ 183.84 ( 1 ) Tungsten in the periodic table Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury ( element ) Thallium Lead Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson Mo ↑ ↓ Sg tantalum ← tungsten → rhenium Atomic number ( Z ) 74 Group, period group 6, period 6 Block d - block Element category transition metal Electron configuration ( Xe ) 4f 5d 6s Electrons per shell 2, 8, 18, 32, 12, 2 Physical properties Phase ( at STP ) solid Melting point 3695 K ​ ( 3422 ° C, ​ 6192 ° F ) Boiling point 6203 K ​ ( 5930 ° C, ​ 10706 ° F ) Density ( near r.t. ) 19.25 g / cm when liquid ( at m.p. ) 17.6 g / cm Heat of fusion 52.31 kJ / mol Heat of vaporization 774 kJ / mol Molar heat capacity 24.27 J / ( mol K ) Vapor pressure P ( Pa ) 10 100 1 k 10 k 100 k at T ( K ) 3477 3773 4137 4579 5127 5823 Atomic properties Oxidation states 6, 5, 4, 3, 2, 1, 0, − 1, − 2, − 4 ​ ( a mildly acidic oxide ) Electronegativity Pauling scale : 2.36 Ionization energies 1st : 770 kJ / mol 2nd : 1700 kJ / mol Atomic radius empirical : 139 pm Covalent radius 162 ± 7 pm Spectral lines Miscellanea Crystal structure ​ body - centered cubic ( bcc ) Speed of sound thin rod 4620 m / s ( at r.t. ) ( annealed ) Thermal expansion 4.5 μm / ( m K ) ( at 25 ° C ) Thermal conductivity 173 W / ( m K ) Electrical resistivity 52.8 nΩ m ( at 20 ° C ) Magnetic ordering paramagnetic Magnetic susceptibility + 59.0 10 cm / mol ( 298 K ) Young 's modulus 411 GPa Shear modulus 161 GPa Bulk modulus 310 GPa Poisson ratio 0.28 Mohs hardness 7.5 Vickers hardness 3430 -- 4600 MPa Brinell hardness 2000 -- 4000 MPa CAS Number 7440 - 33 - 7 History Discovery Carl Wilhelm Scheele ( 1781 ) First isolation Juan José Elhuyar and Fausto Elhuyar ( 1783 ) Named by Torbern Bergman ( 1781 ) Main isotopes of tungsten Isotope Abundance Half - life ( t ) Decay mode Product 0.12 % 1.8 × 10 y α Hf syn 121.2 d ε Ta 26.50 % stable 14.31 % stable 30.64 % stable syn 75.1 d β Re 28.43 % stable view talk references in Wikidata Tungsten, or wolfram, is a chemical element with symbol W and atomic number 74. The name tungsten comes from the former Swedish name for the tungstate mineral scheelite, from tung sten `` heavy stone ''. Tungsten is a rare metal found naturally on Earth almost exclusively in chemical compounds. It was identified as a new element in 1781, and first isolated as a metal in 1783. Its important ores include wolframite and scheelite. The free element is remarkable for its robustness, especially the fact that it has the highest melting point of all the elements discovered, melting at 3422 ° C ( 6192 ° F, 3695 K ). It also has the second highest boiling point, at 5930 ° C ( 10706 ° F, 6203 K ). Its density is 19.3 times that of water, comparable to that of uranium and gold, and much higher ( about 1.7 times ) than that of lead. Polycrystalline tungsten is an intrinsically brittle and hard material ( under standard conditions, when uncombined ), making it difficult to work. However, pure single - crystalline tungsten is more ductile, and can be cut with a hard - steel hacksaw. Tungsten 's many alloys have numerous applications, including incandescent light bulb filaments, X-ray tubes ( as both the filament and target ), electrodes in TIG welding, superalloys, and radiation shielding. Tungsten 's hardness and high density give it military applications in penetrating projectiles. Tungsten compounds are also often used as industrial catalysts. Tungsten is the only metal from the third transition series that is known to occur in biomolecules, where it is used in a few species of bacteria and archaea. It is the heaviest element known to be essential to any living organism. Tungsten interferes with molybdenum and copper metabolism and is somewhat toxic to animal life. Contents 1 Characteristics 1.1 Physical properties 1.2 Isotopes 1.3 Chemical properties 2 History 2.1 Etymology 3 Occurrence 4 Production 5 Applications 5.1 Hard materials 5.2 Alloys 5.3 Armaments 5.4 Chemical applications 5.5 Niche uses 5.6 Gold substitution 5.7 Electronics 5.8 Nanowires 6 Biological role 6.1 In archaea 7 Health factors 8 Patent claim 9 See also 10 References 11 External links Characteristics Physical properties In its raw form, tungsten is a hard steel - grey metal that is often brittle and hard to work. If made very pure, tungsten retains its hardness ( which exceeds that of many steels ), and becomes malleable enough that it can be worked easily. It is worked by forging, drawing, or extruding. Tungsten objects are also commonly formed by sintering. Of all metals in pure form, tungsten has the highest melting point ( 3422 ° C, 6192 ° F ), lowest vapor pressure ( at temperatures above 1650 ° C, 3000 ° F ), and the highest tensile strength. Although carbon remains solid at higher temperatures than tungsten, carbon sublimes at atmospheric pressure instead of melting, so it has no melting point. Tungsten has the lowest coefficient of thermal expansion of any pure metal. The low thermal expansion and high melting point and tensile strength of tungsten originate from strong covalent bonds formed between tungsten atoms by the 5d electrons. Alloying small quantities of tungsten with steel greatly increases its toughness. Tungsten exists in two major crystalline forms : α and β. The former has a body - centered cubic structure and is the more stable form. The structure of the β phase is called A15 cubic ; it is metastable, but can coexist with the α phase at ambient conditions owing to non-equilibrium synthesis or stabilization by impurities. Contrary to the α phase which crystallizes in isometric grains, the β form exhibits a columnar habit. The α phase has one third of the electrical resistivity and a much lower superconducting transition temperature T relative to the β phase : ca. 0.015 K vs. 1 -- 4 K ; mixing the two phases allows obtaining intermediate T values. The T value can also be raised by alloying tungsten with another metal ( e.g. 7.9 K for W - Tc ). Such tungsten alloys are sometimes used in low - temperature superconducting circuits. Isotopes Main article : Isotopes of tungsten Naturally occurring tungsten consists of five isotopes whose half - lives are so long that they can be considered stable. Theoretically, all five can decay into isotopes of element 72 ( hafnium ) by alpha emission, but only W has been observed to do so with a half - life of ( 1.8 ± 0.2 ) × 10 years ; on average, this yields about two alpha decays of W in one gram of natural tungsten per year. The other naturally occurring isotopes have not been observed to decay, constraining their half - lives to be at least 4 × 10 years. Another 30 artificial radioisotopes of tungsten have been characterized, the most stable of which are W with a half - life of 121.2 days, W with a half - life of 75.1 days, W with a half - life of 69.4 days, W with a half - life of 21.6 days, and W with a half - life of 23.72 h. All of the remaining radioactive isotopes have half - lives of less than 3 hours, and most of these have half - lives below 8 minutes. Tungsten also has 4 meta states, the most stable being W ( t 6.4 minutes ). Chemical properties Elemental tungsten resists attack by oxygen, acids, and alkalis. The most common formal oxidation state of tungsten is + 6, but it exhibits all oxidation states from − 2 to + 6. Tungsten typically combines with oxygen to form the yellow tungstic oxide, WO, which dissolves in aqueous alkaline solutions to form tungstate ions, WO 2 − 4. Tungsten carbides ( W C and WC ) are produced by heating powdered tungsten with carbon. W C is resistant to chemical attack, although it reacts strongly with chlorine to form tungsten hexachloride ( WCl ). In aqueous solution, tungstate gives the heteropoly acids and polyoxometalate anions under neutral and acidic conditions. As tungstate is progressively treated with acid, it first yields the soluble, metastable `` paratungstate A '' anion, W 7O6 -- 24, which over time converts to the less soluble `` paratungstate B '' anion, H 2W 12 O10 -- 42. Further acidification produces the very soluble metatungstate anion, H 2W 12 O6 -- 40, after which equilibrium is reached. The metatungstate ion exists as a symmetric cluster of twelve tungsten - oxygen octahedra known as the Keggin anion. Many other polyoxometalate anions exist as metastable species. The inclusion of a different atom such as phosphorus in place of the two central hydrogens in metatungstate produces a wide variety of heteropoly acids, such as phosphotungstic acid H PW O. Tungsten trioxide can form intercalation compounds with alkali metals. These are known as bronzes ; an example is sodium tungsten bronze. History In 1781, Carl Wilhelm Scheele discovered that a new acid, tungstic acid, could be made from scheelite ( at the time named tungsten ). Scheele and Torbern Bergman suggested that it might be possible to obtain a new metal by reducing this acid. In 1783, José and Fausto Elhuyar found an acid made from wolframite that was identical to tungstic acid. Later that year, at the Royal Basque Society in the town of Bergara, 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 at Panasqueira. Tungsten 's desirable properties such as resistance to high temperatures, its hardness and density, and its strengthening of alloys made it an important raw material for the arms industry, both as a constituent of weapons and equipment and employed in production itself, e.g., in tungsten carbide cutting tools for machining steel. Etymology The name `` tungsten '' ( from the Swedish tung sten, `` heavy stone '' ) is used in English, French, and many other languages as the name of the element, but not in the Nordic countries. Tungsten was the old Swedish name for the mineral scheelite. `` Wolfram '' ( or `` volfram '' ) is used in most European ( especially Germanic and Slavic ) languages, and is derived from the mineral wolframite, which is the origin of the chemical symbol W. The name `` wolframite '' is derived from German `` wolf rahm '' ( `` wolf soot '' or `` wolf cream '' ), the name given to tungsten by Johan Gottschalk Wallerius in 1747. This, in turn, derives from `` lupi spuma '', the name Georg Agricola used for the element in 1546, which translates into English as `` wolf 's froth '', and is a reference to the large amounts of tin consumed by the mineral during its extraction. Occurrence Wolframite mineral, with a scale in cm. Tungsten is found mainly in the mineral wolframite ( iron -- manganese tungstate ( Fe, Mn ) WO, which is a solid solution of the two minerals ferberite FeWO, and hübnerite MnWO ) and scheelite ( calcium tungstate ( CaWO ). Other tungsten minerals range in their level of abundance from moderate to very rare, and have almost no economical value. Production Tungsten mined in 2012 About 61,300 tonnes of tungsten concentrates were produced in the year 2009, and in 2010, world production of tungsten was about 68,000 tonnes. The main producers were as follows ( data in tonnes ) : Major producers of tungsten Country Production ( tonnes ) 2009 2011 2012 China 51,000 59,000 61,800 64,000 Russia 2,665 2,785 3,314 3,537 Canada 1,964 420 1,966 2,194 Bolivia 1,023 1,204 1,124 1,247 Vietnam 725 1,150 1,635 1,050 Portugal 823 799 819 763 Austria 887 977 861 706 Rwanda 380 330 520 700 Spain 225 240 497 542 Brazil 192 166 244 381 Australia 33 18 15 290 Peru 502 571 439 276 Burundi 110 100 165 190 Myanmar 874 163 140 140 North Korea 100 110 110 100 Congo 200 25 70 95 Thailand 190 300 160 80 Mongolia 39 20 13 66 Uganda 7 44 8 21 Total 61,200 68,400 73,900 76,400 Tungsten mining in Rwanda forms an important part of the country 's economy. There is additional production in the U.S., but the amount is proprietary company information. U.S. reserves are 140,000 tonnes. US industrial use of wolfram is 20,000 tones : 15,000 tones are imported and the remaining 5,000 tones come from domestic recycling. Tungsten is considered to be a conflict mineral due to the unethical mining practices observed in the Democratic Republic of the Congo. There is a large deposit of tungsten ore on the edge of Dartmoor in the United Kingdom, which was exploited during World War I and World War II as the Hemerdon Mine. With recent increases in tungsten prices, as of 2014 this mine has been reactivated. Tungsten is extracted from its ores in several stages. The ore is eventually converted to tungsten ( VI ) oxide ( WO ), which is heated with hydrogen or carbon to produce powdered tungsten. Because of tungsten 's high melting point, it is not commercially feasible to cast tungsten ingots. Instead, powdered tungsten is mixed with small amounts of powdered nickel or other metals, and sintered. During the sintering process, the nickel diffuses into the tungsten, producing an alloy. Tungsten can also be extracted by hydrogen reduction of WF : WF + 3 H → W + 6 HF or pyrolytic decomposition : WF → W + 3 F ( ΔH = + ) Tungsten is not traded as a futures contract and can not be tracked on exchanges like the London Metal Exchange. The prices are usually quoted for tungsten concentrate or WO. If converted to the metal equivalent, they were about US $19 per kilogram in 2009. Applications Close - up of a tungsten filament inside a halogen lamp Tungsten carbide ring ( jewelry ) 1 kilogram tungsten cylinder ( scale shown below ) Approximately half of the tungsten is consumed for the production of hard materials -- namely tungsten carbide -- with the remaining major use being in alloys and steels. Less than 10 % is used in other chemical compounds. Hard materials Tungsten is mainly used in the production of hard materials based on tungsten carbide, one of the hardest carbides, with a melting point of 2770 ° C. WC is an efficient electrical conductor, but W C is less so. WC is used to make wear - resistant abrasives, and `` carbide '' cutting tools such as knives, drills, circular saws, milling and turning tools used by the metalworking, woodworking, mining, petroleum and construction industries. Carbide tooling is actually a ceramic / metal composite, where metallic cobalt acts as a binding ( matrix ) material to hold the WC particles in place. This type of industrial use accounts for about 60 % of current tungsten consumption. The jewelry industry makes rings of sintered tungsten carbide, tungsten carbide / metal composites, and also metallic tungsten. WC / metal composite rings use nickel as the metal matrix in place of cobalt because it takes a higher luster when polished. Sometimes manufacturers or retailers refer to tungsten carbide as a metal, but it is a ceramic. Because of tungsten carbide 's hardness, rings made of this material are extremely abrasion resistant, and will hold a burnished finish longer than rings made of metallic tungsten. Tungsten carbide rings are brittle, however, and may crack under a sharp blow. Alloys Further information : Tantalum - tungsten alloys The hardness and density of tungsten are applied in obtaining heavy metal alloys. A good example is high speed steel, which can contain as much as 18 % tungsten. Tungsten 's high melting point makes tungsten a good material for applications like rocket nozzles, for example in the UGM - 27 Polaris submarine - launched ballistic missile. Tungsten alloys are used in a wide range of different applications, including the aerospace and automotive industries and radiation shielding. Superalloys containing tungsten, such as Hastelloy and Stellite, are used in turbine blades and wear - resistant parts and coatings. Quenched ( martensitic ) tungsten steel ( approx. 5.5 % to 7.0 % W with 0.5 % to 0.7 % C ) was used for making hard permanent magnets, due to its high remanence and coercivity, as noted by John Hopkinson ( 1849 - 1898 ) as early as 1886. The magnetic properties of a metal or an alloy are very sensitive to microstructure. For example, while the element tungsten is not ferromagnetic ( but iron, of course, is ), when present in steel in these proportions, it stabilizes the martensite phase, which has an enhanced ferromagnetism, as compared to the ferrite ( iron ) phase, due to its greater resistance to magnetic domain wall motion. Tungsten 's heat resistance makes it useful in arc welding applications when combined with another highly - conductive metal such as silver or copper. The silver or copper provides the necessary conductivity and the tungsten allows the welding rod to withstand the high - temperatures of the arc welding environment. Armaments Tungsten, usually alloyed with nickel and iron or cobalt to form heavy alloys, is used in kinetic energy penetrators as an alternative to depleted uranium, in applications where uranium 's radioactivity is problematic even in depleted form, or where uranium 's additional pyrophoric properties are not required ( for example, in ordinary small arms bullets designed to penetrate body armor ). Similarly, tungsten alloys have also been used in cannon shells, grenades and missiles, to create supersonic shrapnel. Germany used tungsten during World War II to produce shells for anti-tank gun designs using the Gerlich `` squeeze '' principle to achieve very high muzzle velocity and enhanced armor penetration from comparatively small caliber and light weight field artillery. The weapons were highly effective but a shortage of tungsten used in the shell core limited that effectiveness. Tungsten has also been used in Dense Inert Metal Explosives, which use it as dense powder to reduce collateral damage while increasing the lethality of explosives within a small radius. Chemical applications Tungsten ( IV ) sulfide is a high temperature lubricant and is a component of catalysts for hydrodesulfurization. MoS is more commonly used for such applications. Tungsten oxides are used in ceramic glazes and calcium / magnesium tungstates are used widely in fluorescent lighting. Crystal tungstates are used as scintillation detectors in nuclear physics and nuclear medicine. Other salts that contain tungsten are used in the chemical and tanning industries. Tungsten trioxide powder Tungsten oxide ( WO ) is incorporated into selective catalytic reduction ( SCR ) catalysts found in coal - fired power plants. These catalysts convert nitrogen oxides ( NO ) to nitrogen ( N ) and water ( H O ) using ammonia ( NH ). The tungsten oxide helps with the physical strength of the catalyst and extends catalyst life. Niche uses Applications requiring its high density include weights, counterweights, ballast keels for yachts, tail ballast for commercial aircraft, and as ballast in race cars for NASCAR and Formula One ; depleted uranium is also used for these purposes, due to similarly high density. Seventy - five - kg blocks of tungsten were used as `` cruise balance mass devices '' on the entry vehicle portion of the 2012 Mars Science Laboratory spacecraft. It is an ideal material to use as a dolly for riveting, where the mass necessary for good results can be achieved in a compact bar. High - density alloys of tungsten with nickel, copper or iron are used in high - quality darts ( to allow for a smaller diameter and thus tighter groupings ) or for fishing lures ( tungsten beads allow the fly to sink rapidly ). Some cello C strings are wound with tungsten. The extra density gives this string more projection and often cellists will buy just this string and use it with three strings from a different set. Tungsten is used as an absorber on the electron telescope on the Cosmic Ray System of the two Voyager spacecraft. Sodium tungstate is used in Folin - Ciocalteu 's reagent, a mixture of different chemicals used in the `` Lowry Assay '' for protein content analysis. Gold substitution Its density, similar to that of gold, allows tungsten to be used in jewelry as an alternative to gold or platinum. Metallic tungsten is hypoallergenic, and is harder than gold alloys ( though not as hard as tungsten carbide ), making it useful for rings that will resist scratching, especially in designs with a brushed finish. Because the density is so similar to that of gold ( tungsten is only 0.36 % less dense ), tungsten can also be used in counterfeiting of gold bars, such as by plating a tungsten bar with gold, which has been observed since the 1980s, or taking an existing gold bar, drilling holes, and replacing the removed gold with tungsten rods. The densities are not exactly the same, and other properties of gold and tungsten differ, but gold - plated tungsten will pass superficial tests. Gold - plated tungsten is available commercially from China ( the main source of tungsten ), both in jewelry and as bars. Electronics Because it retains its strength at high temperatures and has a high melting point, elemental tungsten is used in many high - temperature applications, such as light bulb, cathode - ray tube, and vacuum tube filaments, heating elements, and rocket engine nozzles. Its high melting point also makes tungsten suitable for aerospace and high - temperature uses such as electrical, heating, and welding applications, notably in the gas tungsten arc welding process ( also called tungsten inert gas ( TIG ) welding ). Tungsten electrode used in a Gas tungsten arc welding torch Because of its conductive properties and relative chemical inertness, tungsten is also used in electrodes, and in the emitter tips in electron - beam instruments that use field emission guns, such as electron microscopes. In electronics, tungsten is used as an interconnect material in integrated circuits, between the silicon dioxide dielectric material and the transistors. It is used in metallic films, which replace the wiring used in conventional electronics with a coat of tungsten ( or molybdenum ) on silicon. The electronic structure of tungsten makes it one of the main sources for X-ray targets, and also for shielding from high - energy radiations ( such as in the radiopharmaceutical industry for shielding radioactive samples of FDG ). It is also used in gamma imaging as a material from which coded apertures are made, due to its excellent shielding properties. 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 is used for making glass - to - metal seals. In addition to its high melting point, when tungsten is doped with potassium, it leads to an increased shape stability ( compared to non-doped tungsten ). This ensures that the filament does not sag, and no undesired changes occur. Nanowires Through top - down nanofabrication processes, tungsten nanowires have been fabricated and studied since 2002. Due to a particularly high surface to volume ratio, the formation of a surface oxide layer and the single crystal nature of such material, the mechanical properties differ fundamentally from those of bulk tungsten. Such tungsten nanowires have potential applications in nanoelectronics and importantly as pH probes and gas sensors. In similarity to silicon nanowires, tungsten nanowires are frequently produced from a bulk tungsten precursor followed by a thermal oxidation step to control morphology in terms of length and aspect ratio. Using the Deal -- Grove model it is possible to predict the oxidation kinetics of nanowires fabricated through such thermal oxidation processing. Biological role Tungsten, at atomic number 74, is the heaviest element known to be biologically functional, with the next heaviest being iodine ( Z = 53 ). It is used by some bacteria and archaea, but not in eukaryotes. 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 in use by living organisms ). Tungsten - using enzymes typically reduce carboxylic acids to aldehydes. The tungsten oxidoreductases may also catalyse oxidations. 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 dehydrogenase H ) is known to use a selenium - molybdenum version of molybdopterin. Acetylene hydratase is an unusual metalloenzyme in that it catalyzes a hydration reaction. Two reaction mechanisms have been proposed, in one of which there is a direct interaction between the tungsten atom and the C ≡ C triple bond. Although a tungsten - containing xanthine dehydrogenase from bacteria has been found to contain tungsten - molydopterin and also non-protein bound selenium, a tungsten - selenium molybdopterin complex has not been definitively described. In soil, tungsten metal oxidizes to the tungstate anion. It can be selectively or non-selectively imported by some prokaryotic organisms and may substitute for molybdate in certain enzymes. Its effect on the action of these enzymes is in some cases inhibitory and in others positive. The soil 's chemistry determines how the tungsten polymerizes ; alkaline soils cause monomeric tungstates ; acidic soils cause polymeric tungstates. Sodium tungstate and lead have been studied for their effect on earthworms. Lead was found to be lethal at low levels and sodium tungstate was much less toxic, but the tungstate completely inhibited their reproductive ability. Tungsten has been studied as a biological copper metabolic antagonist, in a role similar to the action of molybdenum. It has been found that tetrathiotungstates may be used as biological copper chelation chemicals, similar to the tetrathiomolybdates. In archaea Tungsten is essential for some archaea. The following tungsten - utilizing enzymes are known : Aldehyde ferredoxin oxidoreductase ( AOR ) in Thermococcus strain ES - 1 Formaldehyde ferredoxin oxidoreductase ( FOR ) in Thermococcus litoralis Glyceraldehyde - 3 - phosphate ferredoxin oxidoreductase ( GAPOR ) in Pyrococcus furiosus A wtp system is known to selectively transport tungsten in archaea : WtpA is tungten - binding protein of ABC family of transporters WptB is a permease WtpC is ATPase Health factors Because tungsten is rare and its compounds are generally inert, the effects of tungsten on the environment are limited. It was first believed to be relatively inert and an only slightly toxic metal, beginning in the year 2000, the risk exerted by tungsten alloys, its dusts and particulates to induce cancer and several other adverse effects in animals as well as humans has been highlighted from in vitro and in vivo experiments. The median lethal dose LD depends strongly on the animal and the method of administration and varies between 59 mg / kg ( intravenous, rabbits ) and 5000 mg / kg ( tungsten metal powder, intraperitoneal, rats ). People can be exposed to tungsten in the workplace by breathing it in, swallowing it, skin contact, and eye contact. The National Institute for Occupational Safety and Health ( NIOSH ) has set a recommended exposure limit ( REL ) of 5 mg / m over an 8 - hour workday and a short term limit of 10 mg / m. Patent claim Tungsten is unique amongst the elements in that it has been the subject of patent proceedings. In 1928, a US court rejected General Electric 's attempt to patent it, overturning U.S. Patent 1,082,933 granted in 1913 to William D. Coolidge. See also Field emission gun Tungsten oxide List of chemical elements name etymologies List of chemical elements naming controversies References Jump up ^ Meija, J. ; et al. 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Jump up ^ Koutsospyros, A. ; Braida, W. ; Christodoulatos, C. ; Dermatas, D. ; Strigul, N. ( 2006 ). `` A review of tungsten : From environmental obscurity to scrutiny ''. Journal of Hazardous Materials. 136 ( 1 ) : 1 -- 19. doi : 10.1016 / j. jhazmat. 2005.11. 007. PMID 16343746. Jump up ^ Lagarde, F. ; Leroy, M. ( 2002 ). `` Metabolism and toxicity of tungsten in humans and animals ''. Metal ions in biological systems. 39 : 741 -- 59. doi : 10.1201 / 9780203909331. ch22. PMID 11913143. also reported in Astrid Sigel ; Helmut Sigel ( 2002 ). Molybdenum and tungsten : their roles in biological processes. CRC Press. p. 741 ff. ISBN 0 - 8247 - 0765 - 6. Jump up ^ Masten, Scott ( 2003 ). `` Tungsten and Selected Tungsten Compounds -- Review of Toxicological Literature '' ( PDF ). National Institute of Environmental Health Sciences. Archived from the original ( PDF ) on 2009 - 03 - 25. Retrieved 2009 - 03 - 19. Jump up ^ Marquet, P. ; et al. ( 1997 ). `` Tungsten determination in biological fluids, hair and nails by plasma emission spectrometry in a case of severe acute intoxication in man ''. Journal of forensic sciences. 42 ( 3 ) : 527 -- 30. PMID 9144946. Jump up ^ `` CDC -- NIOSH Pocket Guide to Chemical Hazards -- Tungsten ''. www.cdc.gov. Archived from the original on 2015 - 11 - 25. Retrieved 2015 - 11 - 24. Jump up ^ General Electric Co. v. De Forest Radio Co., 28 F. 2d 641, 643 ( 3rd Cir. 1928 ) Jump up ^ Guruswamy, Lakshman D. ; McNeely, Jeffrey A. ( 1998 ). Protection of global biodiversity : converging strategies. Duke University Press. pp. 333 --. ISBN 978 - 0 - 8223 - 2188 - 0. Archived from the original on 2013 - 05 - 30. External links Wikimedia Commons has media related to Tungsten. Look up tungsten in Wiktionary, the free dictionary. Properties, Photos, History, MSDS CDC -- NIOSH Pocket Guide to Chemical Hazards Tungsten at The Periodic Table of Videos ( University of Nottingham ) Picture in the collection from Heinrich Pniok Elementymology & Elements Multidict by Peter van der Krogt -- Tungsten International Tungsten Industry Association Periodic table ( Large cells ) 5 6 7 8 9 10 11 12 13 14 15 16 17 18 He Li Be O Ne Na Mg Al Si Cl Ar Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 5 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te Xe 6 Cs Ba La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Hf Ta Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn 7 Fr Ra Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og Alkali metal Alkaline earth metal Lanthanide Actinide Transition metal Post - ​ transition metal Metalloid Polyatomic nonmetal Diatomic nonmetal Noble gas Unknown chemical properties Tungsten compounds Tungsten ( 0 ) W ( CO ) Tungsten ( II ) WSi WCl W ( OH ) Tungsten ( III ) W O Tungsten ( IV ) WC WO WS WSe WTe WF WCl Tungsten ( V ) W O WBr W Cl Tungsten ( VI ) H PW O WO Cl WCl WF WN WO WS WOBr WOCl WOF H WO Organotungsten ( VI ) compounds W ( CH ) Tungsten minerals Hydrokenoelsmoreite Ferberite Hübnerite Raspite Russellite Scheelite Stolzite Tungstite Wolframite Jewellery Forms Anklet Barrette Belt buckle Belly chain Bindi Bolo tie Bracelet Brooch Chatelaine Collar pin Crown Cufflink Earring Ferronnière Lapel pin Necklace Pectoral Pendant Ring Tiara Tie chain Tie clip Tie pin Toe ring Watch pocket strap Making People Bench jeweler Clockmaker Goldsmith Silversmith Jewelry designer Lapidary Watchmaker Processes Carving Casting centrifugal lost - wax vacuum Enameling Engraving Filigree Kazaziye Metal clay Plating Polishing Repoussé and chasing Soldering Stonesetting Wire sculpture Wire wrapped jewelry Tools Draw plate File Hammer Mandrel Pliers Materials Precious metals Gold Palladium Platinum Rhodium Silver Precious metal alloys Britannia silver Colored gold Crown gold Electrum Shakudō Shibuichi Sterling silver Tumbaga Base metals Brass Bronze Copper Mokume - gane Pewter Stainless steel Titanium Tungsten Mineral gemstones Aventurine Agate Amethyst Beryl Carnelian Chrysoberyl Diamond Diopside Emerald Garnet Jade Jasper Lapis lazuli Larimar Malachite Marcasite Moonstone Obsidian Onyx Opal Pearl Peridot Prasiolite Quartz Ruby Sapphire Sodalite Spinel Sunstone Tanzanite Tiger 's eye Topaz Tourmaline Turquoise Zircon Organic gemstones Abalone Amber Ammolite Copal Coral Ivory Jet Nacre Other natural objects Bog - wood Hair Shell jewelry Toadstone Terms Carat ( mass ) Carat ( purity ) Finding Millesimal fineness Art jewelry Related topics Body piercing Fashion Gemology Phaleristics Metalworking Wearable art LCCN : sh85138607 GND : 4066862 - 9 NDL : 00572649 Retrieved from `` https://en.wikipedia.org/w/index.php?title=Tungsten&oldid=819216503 '' Categories : Tungsten minerals Tungsten Chemical elements Transition metals Biology and pharmacology of chemical elements Refractory metals Hidden categories : Webarchive template wayback links CS1 maint : Unfit url CS1 maint : Multiple names : authors list All articles lacking reliable references Articles lacking reliable references from October 2017 Wikipedia articles needing clarification from February 2016 Good articles Wikipedia articles with LCCN identifiers Wikipedia articles with GND identifiers Talk Contents About Wikipedia Tools Afrikaans አማርኛ Aragonés Armãneashti Asturianu Azərbaycanca বাংলা Bân - lâm - gú Беларуская Беларуская ( тарашкевіца ) ‎ भोजपुरी Български བོད ་ ཡིག Bosanski Brezhoneg Català Чӑвашла Cebuano Čeština Corsu Cymraeg Dansk Deutsch Eesti Ελληνικά Эрзянь Español Esperanto Euskara فارسی Fiji Hindi Français Furlan Gaeilge Gaelg Gàidhlig Galego ગુજરાતી 客家 語 / Hak - kâ - ngî Хальмг 한국어 Հայերեն हिन्दी Hrvatski Ido Bahasa Indonesia Interlingua Íslenska Italiano עברית ಕನ್ನಡ ქართული Қазақша Kiswahili Коми Kurdî Кыргызча Кырык мары Latina Latviešu Lëtzebuergesch Lietuvių Ligure Limburgs La. lojban. 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Question: is tungsten a metal or nonmetal or metalloid
Answer: rare metal