Tungsten
Tungsten | |||||||||||||||||||||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Pronunciation | /ˈtʌŋstən/ | ||||||||||||||||||||||||||||||||||||||||||||||||||
Alternative name | wolfram, pronounced: /ˈwʊlfrəm/ (WUUL-frəm) | ||||||||||||||||||||||||||||||||||||||||||||||||||
Allotropes | α-tungsten (common), β-tungsten | ||||||||||||||||||||||||||||||||||||||||||||||||||
Appearance | grayish white, lustrous | ||||||||||||||||||||||||||||||||||||||||||||||||||
Standard atomic weight Ar°(W) | |||||||||||||||||||||||||||||||||||||||||||||||||||
Tungsten in the periodic table | |||||||||||||||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||
Heat of vaporization | 774 kJ/mol | ||||||||||||||||||||||||||||||||||||||||||||||||||
Molar heat capacity | 24.27 J/(mol·K) | ||||||||||||||||||||||||||||||||||||||||||||||||||
Vapor pressure
| |||||||||||||||||||||||||||||||||||||||||||||||||||
Atomic properties | |||||||||||||||||||||||||||||||||||||||||||||||||||
Discovery and first isolation | Juan José Elhuyar and Fausto Elhuyar[9] (1783) | ||||||||||||||||||||||||||||||||||||||||||||||||||
Named by | Torbern Bergman (1781) | ||||||||||||||||||||||||||||||||||||||||||||||||||
Symbol | "W": from Wolfram, originally from Middle High German wolf-rahm 'wolf's foam' describing the mineral wolframite[10] | ||||||||||||||||||||||||||||||||||||||||||||||||||
Isotopes of tungsten | |||||||||||||||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||
Tungsten (also called wolfram)
The
Tungsten occurs in many alloys, which have numerous applications, including incandescent
Tungsten is the only metal in the third transition series that is known to occur in biomolecules, being found in a few species of bacteria and archaea. However, tungsten interferes with molybdenum and copper metabolism and is somewhat toxic to most forms of animal life.[19][20]
Characteristics
Physical properties
In its raw form, tungsten is a hard steel-grey
Of all metals in pure form, tungsten has the highest
Tungsten exists in two major
Isotopes
Naturally occurring tungsten consists of four stable
Bi (its longest lived isotope) actually decays with a half life of 2.01×1019 years or about a factor 10 slower than 180
W. However, due to naturally occurring bismuth being 100% 209
Bi, its specific activity is actually higher than that of natural tungsten at 3 milli-becquerel per kilogram. The other naturally occurring isotopes of tungsten have not been observed to decay, constraining their half-lives to be at least 4×1021 years.
Another 34 artificial
Chemical properties
Tungsten is a mostly non-reactive element: it does not react with water, is immune to attack by most acids and bases, and does not react with oxygen or air at room temperature. At elevated temperatures (i.e., when red-hot) it reacts with oxygen to form the
The most common formal oxidation state of tungsten is +6, but it exhibits all oxidation states from −2 to +6.[35][36] Tungsten typically combines with oxygen to form the yellow tungstic oxide, WO3, which dissolves in aqueous alkaline solutions to form tungstate ions, WO2−
4.
Tungsten carbides (W2C and WC) are produced by heating powdered tungsten with carbon. W2C is resistant to chemical attack, although it reacts strongly with chlorine to form tungsten hexachloride (WCl6).[14]
In aqueous solution, tungstate gives the
7O6−
24, which over time converts to the less soluble "paratungstate B" anion, H
2W
12O10−
42.[37] Further acidification produces the very soluble metatungstate anion, H
2W
12O6−
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
Tungsten trioxide can form intercalation compounds with alkali metals. These are known as bronzes; an example is sodium tungsten bronze.
In gaseous form, tungsten forms the diatomic species W2. These molecules feature a
History
In 1781, Carl Wilhelm Scheele discovered that a new acid, tungstic acid, could be made from scheelite (at the time called tungsten).[40][41] Scheele and Torbern Bergman suggested that it might be possible to obtain a new metal by reducing this acid.[42] 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 (they called it "wolfram" or "volfram").[43][44][45][46][47]
The strategic value of tungsten came to notice in the early 20th century. British authorities acted in 1912 to free the Carrock mine from the German owned Cumbrian Mining Company and, during World War I, restrict German access elsewhere.[48] In World War II, tungsten played a more 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,[49][50] both as a constituent of weapons and equipment and employed in production itself, e.g., in tungsten carbide cutting tools for machining steel. Now tungsten is used in many more applications such as aircraft and motorsport ballast weights, darts, anti-vibration tooling, and sporting equipment.
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.[51][52][53]
Etymology
The name tungsten (which means 'heavy stone' in
(c.f. "Old Nick") derive their names from the same miner's idiom.Occurrence
Tungsten has thus far not been found in nature in its pure form.[54] Instead, tungsten is found mainly in the minerals wolframite and scheelite.[54] Wolframite is iron–manganese tungstate (Fe,Mn)WO4, a solid solution of the two minerals ferberite (FeWO4) and hübnerite (MnWO4), while scheelite is calcium tungstate (CaWO4). Other tungsten minerals range in their level of abundance from moderate to very rare, and have almost no economic value.
Chemical compounds
Tungsten forms chemical compounds in oxidation states from -II to VI. Higher oxidation states, always as oxides, are relevant to its terrestrial occurrence and its biological roles, mid-level oxidation states are often associated with
The broad range of oxidation states of tungsten is reflected in its various chlorides:[55]
- Tungsten(II) chloride, which exists as the hexamer W6Cl12
- Tungsten(III) chloride, which exists as the hexamer W6Cl18
- Tungsten(IV) chloride, WCl4, a black solid, which adopts a polymeric structure.
- Tungsten(V) chloride WCl5, a black solid which adopts a dimeric structure.
- Tungsten(VI) chlorideWCl6, which contrasts with the instability of MoCl6.
Production
Reserves
The world's reserves of tungsten are 3,200,000 tonnes; they are mostly located in China (1,800,000 t), Canada (290,000 t),[57] Russia (160,000 t), Vietnam (95,000 t) and Bolivia. As of 2017, China, Vietnam and Russia are the leading suppliers with 79,000, 7,200 and 3,100 tonnes, respectively. Canada had ceased production in late 2015 due to the closure of its sole tungsten mine. Meanwhile, Vietnam had significantly increased its output in the 2010s, owing to the major optimization of its domestic refining operations, and overtook Russia and Bolivia.[58]
China remains the world's leader not only in production, but also in export and consumption of tungsten products. Tungsten production is gradually increasing outside China because of the rising demand. Meanwhile, its supply by China is strictly regulated by the Chinese Government, which fights illegal mining and excessive pollution originating from mining and refining processes.[59]
There is a large deposit of tungsten ore on the edge of
Within the EU, the Austrian Felbertal scheelite deposit is one of the few producing tungsten mines.[62] Portugal is one of Europe's main tungsten producers, with 121 kt of contained tungsten in mineral concentrates from 1910 to 2020, accounting for roughly 3.3% of the global production.[63]
Tungsten is considered to be a
Extraction
Tungsten is extracted from its ores in several stages. The ore is eventually converted to
Tungsten can also be extracted by hydrogen reduction of WF6:
- WF6 + 3 H2 → W + 6 HF
or pyrolytic decomposition:[66]
- WF6 → W + 3 F2 (ΔHr= +)
Tungsten is not traded as a futures contract and cannot be tracked on exchanges like the London Metal Exchange. The tungsten industry often uses independent pricing references such as Argus Media or Metal Bulletin as a basis for contracts.[67] The prices are usually quoted for tungsten concentrate or WO3.[58]
Applications
Approximately half of the tungsten is consumed for the production of hard materials – namely
Industrial
Tungsten is mainly used in the production of hard materials based on
The
Alloys
The hardness and heat resistance of tungsten can contribute to useful
blades and wear-resistant parts and coatings.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.[77]
Permanent magnets
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 is), when it is present in steel in these proportions, it stabilizes the martensite phase, which has greater ferromagnetism than the ferrite (iron) phase due to its greater resistance to magnetic domain wall motion.
Military
Tungsten, usually alloyed with
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.[78]
Chemical applications
Tungsten
Niche uses
Applications requiring its high density include weights,
Gold substitution
Its density, similar to that of gold, allows tungsten to be used in jewelry as an alternative to
Because the density is so similar to that of gold (tungsten is only 0.36% less dense), and its price of the order of one-thousandth, tungsten can also be used in
Gold-plated tungsten is available commercially from China (the main source of tungsten), both in jewelry and as bars.[100]
Electronics
Because it retains its strength at high temperatures and has a high melting point, elemental tungsten is used in many high-temperature applications,[101] such as incandescent light bulb, cathode-ray tube, and vacuum tube filaments, heating elements, and rocket engine nozzles.[18] 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).[102]
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.[66]
The electronic structure of tungsten makes it one of the main sources for
Nanowires
Through top-down
Fusion power
Due to its high melting point and good erosion resistance, tungsten is a lead candidate for the most exposed sections of the plasma-facing inner wall of nuclear fusion reactors. It will be used as the plasma-facing material of the divertor in the ITER reactor,[111] and is currently in use in the JET test reactor.
Biological role
Tungsten, at atomic number Z = 74, is the heaviest element known to be biologically functional. It is used by some bacteria and
In soil, tungsten metal oxidizes to the
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.[120]
Tungsten has been studied as a biological copper metabolic antagonist, in a role similar to the action of molybdenum. It has been found that tetrathiotungstate salts may be used as biological copper chelation chemicals, similar to the tetrathiomolybdates.[121]
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 tungsten-binding protein of ABC family of transporters
- WptB is a permease
- WtpC is ATPase[122]
Health factors
Because tungsten is a rare metal[123] and its compounds are generally inert, the effects of tungsten on the environment are limited.[124] The abundance of tungsten in the Earth's crust is thought to be about 1.5 parts per million. It is one of the rarer elements.
It was at first believed to be relatively inert and an only slightly toxic metal, but beginning in the year 2000, the risk presented 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.[125][126] The median lethal dose LD50 depends strongly on the animal and the method of administration and varies between 59 mg/kg (intravenous, rabbits)[127][128] and 5000 mg/kg (tungsten metal powder, intraperitoneal, rats).[129][130]
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/m3 over an 8-hour workday and a short term limit of 10 mg/m3.[131]
In popular culture
Tungsten and tungsten alloys gained popularity through tungsten cubes and spheres. This popularity started in October 2021, and rose again in January 2023, through social media.[132]
The main reason that tungsten cubes, spheres and other forms became popular is for their novelty as an item, due to their density. No other element comes close to the same density with regards to cost and availability, with some being radioactive as well.
See also
- Field emission gun
- Tungsten oxide
- List of chemical elements name etymologies
- List of chemical elements naming controversies
References
- ^ "Standard Atomic Weights: Tungsten". CIAAW. 1991.
- ISSN 1365-3075.
- ^ Berger, Dan. "Why does Tungsten not 'Kick' up an electron from the s sublevel ?". Bluffton College, USA.
- ^ ISBN 978-1-62708-155-9.
- ISBN 978-1-4200-9084-0.
- S2CID 99610871.
- ISBN 978-0-8493-0486-6. Archived from the original(PDF) on 2011-03-03.
- ISBN 978-0-8493-0464-4.
- ^ "Tungsten". Royal Society of Chemistry. Royal Society of Chemistry. Retrieved May 2, 2020.
- ^ a b van der Krogt, Peter. "Wolframium Wolfram Tungsten". Elementymology& Elements Multidict. Archived from the original on 2010-01-23. Retrieved 2010-03-11.
- ^ "wolfram" on Merriam-Webster.
- ^ "wolfram" on Oxford Dictionaries.
- doi:10.1021/je1011086.)
{{cite journal}}
: CS1 maint: multiple names: authors list (link - ^ ISBN 978-0-8160-5649-1.
- ISBN 978-0-306-45053-2.
- S2CID 137928096.
- S2CID 137145004.
- ^ ISBN 978-0-19-515026-1.
- PMID 9667924.
- PMID 12114025.
- ^ ISBN 978-0-8493-0485-9.
- PMID 17003900.
- ISBN 978-0-306-45053-2.
- ^ Bean, Heather (October 19, 1998). Material Properties and Analysis Techniques for Tungsten Thin Films. frii.com
- (PDF) from the original on 2013-05-13.
- .
- .
- S2CID 119351442.
- S2CID 54624704.
- PMID 9941272.
- S2CID 6733875.
- S2CID 118891861.
- ^ a b c Sonzogni, Alejandro. "Interactive Chart of Nuclides". National Nuclear Data Center: Brookhaven National Laboratory. Archived from the original on 2008-05-22. Retrieved 2008-06-06.
- ^ "Tungsten: reactions of elements".
- ^ ISBN 978-0-19-855569-8.
- .
- doi:10.1071/CH00140.
- ISSN 0301-0104.
- PMID 17225237.
- ^ Scheele, Carl Wilhelm (1781) "Tungstens bestånds-delar" (Tungsten's constituents), Kungliga Vetenskaps Academiens Nya Handlingar (Royal Scientific Academy's New Proceedings), 2 : 89–95 (in Swedish).
- ^ English translation on pp. 4–13 of: de Luyart, John Joseph and Fausto, with Charles Cullen, trans., A Chemical Analysis of Wolfram and Examination of a New Metal, Which Enters its Composition (London, England, G. Nicol, 1785).
- ^ ISBN 978-1-4034-3518-7.
- ^ "ITIA Newsletter" (PDF). International Tungsten Industry Association. June 2005. Archived from the original on July 21, 2011. Retrieved 2008-06-18.
{{cite news}}
: CS1 maint: unfit URL (link) - ^ "ITIA Newsletter" (PDF). International Tungsten Industry Association. December 2005. Archived from the original on July 21, 2011. Retrieved 2008-06-18.
{{cite news}}
: CS1 maint: unfit URL (link) - ^ de Luyart, J.J. and F. (September 1783) "Análisis químico del volfram, y examen de un nuevo metal, que entra en su composición" (Chemical analysis of wolframite, and examination of a new metal, which enters into its composition), Extractos de las Juntas Generales celebradas por la Real Sociedad Bascongada de los Amigos del País en la ciudad de Vitoria por setiembre de 1783, pp. 46–88.
- ^ de Luyart, John Joseph and Fausto, with Charles Cullen, trans., A Chemical Analysis of Wolfram and Examination of a New Metal, Which Enters its Composition (London, England, G. Nicol, 1785).
- ^ Caswell, Lyman R. and Stone Daley, Rebecca W. (1999) "The Delhuyar brothers, tungsten, and Spanish silver," Bulletin for the History of Chemistry, 23 : 11–19. Available at: University of Illinois (USA) Archived 2015-12-30 at the Wayback Machine
- ^ Watson, Greig (2014-06-06). "Vital WW1 metal 'in enemy hands'". BBC News. Retrieved 2018-02-10.
- .
- JSTOR 3513391.
- ^ General Electric Co. v. De Forest Radio Co., 28 F.2d 641, 643 (3rd Cir. 1928)
- ISBN 978-0-8223-2188-0.
- ^ General Electric Co. v. De Forest Radio Co., 28 F.2d 641 (3d Cir. 1928).
- ^ a b "Tungsten, W, atomic number 74". Institute of rare earths elements and strategic metals.
- ^ ISBN 978-3-11-007511-3.
- .
- ^ Tungsten. Mineral Commodity Summaries. USGS (2017)
- ^ a b Shedd, Kim B. (December 2018) Tungsten. 2016 Minerals Yearbook. USGS
- ^ Tungsten. Mineral Commodity Summaries. USGS (2018)
- ^ "Work starts on £130m Devon tungsten mine". BBC News. 9 June 2014. Archived from the original on 2014-12-05.
- ^ "How Hemerdon mine lost £100m in just three years". Plymouth Herald. 12 October 2018. Retrieved 24 January 2019.
- S2CID 233912162.
- ISSN 2079-9276.
- ^ Kristof, Nicholas D. (2010-06-27). "Death by Gadget". The New York Times. Archived from the original on 2016-08-31.
- ^ "The Genocide Behind Your Smart Phone". The Daily Beast. July 16, 2010. Archived from the original on 2011-11-17.
- ^ a b Schey, John A. (1987). Introduction to Manufacturing Processes (2nd ed.). McGraw-Hill, Inc.
- ^ "Tungsten Pricing". International Tungsten Industry Association. Retrieved 18 June 2020.
- .
- PMID 29707073.
- ^ Don Law-West; Louis Perron. "Tungsten". The Canadian Encyclopaedia. Retrieved 2020-07-18.
- ^ Tungsten: The Element, History, Uses and Wedding Bands.tungstenworld.com
- ISBN 978-1-59921-397-2.
- ISBN 978-0-470-44431-3.
- ^ "Tungsten Applications – Steel". Azom. 2000–2008. Archived from the original on 2008-08-15. Retrieved 2008-06-18.
- ISBN 978-81-224-2030-2.
- ^ "Tungsten Applications". wolfmet.com. Archived from the original on 2013-09-01.
- ^ "TIG Torches & TIG Torch Parts". AES Industrial Supplies Limited. Retrieved 2021-05-06.
- ^ Dense Inert Metal Explosive (DIME). Defense-update.com. Retrieved on 2011-08-07.
- ISBN 978-0-444-50214-8. Retrieved 18 December 2011.
- ISBN 978-3-527-61033-4.
- ISBN 978-0-85404-224-1. Retrieved 18 December 2011.
- ISSN 1878-5204.
- ^ Kinetic studies of propane oxidation on Mo and V based mixed oxide catalysts. 2011. pp. 165–170.
- .
- ISSN 1878-5204.
- S2CID 220948033.
- S2CID 213246090.
- ^ "F1 Technique: The secrets of ballast in a Formula 1 car". Auto123.com. 2013-12-25. Retrieved 2019-02-03.
- ISBN 978-0-7614-1548-0.
- ^ Duchaine, Simon (2018-03-09). "The Tungsten Carbide Nozzle Offers a Balance Between Wear Resistance and High Performance". 3dprint.com. Retrieved 2018-10-23.
- ISBN 978-0-292-72393-1.
- ^ Pickering N. C. (1991). The Bowed String: Observations on the Design, Manufacture, Testing and Performance of Strings for Violins, Violas and Cellos. Amereon, Mattituck, New York. pp. 5–6, 17.
{{cite book}}
: CS1 maint: location missing publisher (link) - ^ "CRS Instruments". NASA. Archived from the original on 2017-02-01.
- ISBN 978-0-313-33507-5.
- ^ a b Gray, Theo (March 14, 2008). "How to Make Convincing Fake-Gold Bars". Popular Science. Archived from the original on December 29, 2014. Retrieved 2008-06-18.
- ^ "Zinc Dimes, Tungsten Gold & Lost Respect Archived 2011-10-08 at the Wayback Machine", Jim Willie, Nov 18 2009
- ^ "Largest Private Refinery Discovers Gold-Plated Tungsten Bar – Coin Update". news.coinupdate.com.
- ^ "Austrians Seize False Gold Tied to London Bullion Theft". The New York Times. Reuters. 1983-12-22. Archived from the original on 2012-03-27. Retrieved 2012-03-25.
- ^ Tungsten filled Gold bars Archived 2012-03-26 at the Wayback Machine, ABC Bullion, Thursday, March 22, 2012
- ^ Tungsten Alloy for Gold Substitution Archived 2012-03-22 at the Wayback Machine, China Tungsten
- ^ DeGarmo, E. Paul (1979). Materials and Processes in Manufacturing (5th ed.). New York: MacMillan Publishing.
- ISBN 978-0-13-113029-6.)
{{cite book}}
: CS1 maint: location (link - ISBN 978-0-8121-1310-5. Archivedfrom the original on 2017-11-11.
- ^ Hasz, Wayne Charles et al. (August 6, 2002) "X-ray target" U.S. patent 6,428,904
- ^ "Non-Sag Doped Tungsten – Union City Filament". Union City Filament. Retrieved 2017-04-28.
- PMID 12491423.
- .
- ^ CNR Rao (2006). "High-sensitivity hydrocarbon sensors based on tungsten oxide nanowires". Journal of Materials Chemistry.
- .
- (PDF) from the original on 2017-03-15.
- ISSN 0022-3115.
- PMID 8444863.)
{{cite journal}}
: CS1 maint: multiple names: authors list (link - ISBN 978-0-306-45053-2.
- (PDF) from the original on 2008-12-03.
- PMID 9521673.
- PMID 25416389.
- PMID 10491134.
- S2CID 19459237.
- .
- S2CID 38620368.
- PMID 8133256.
- ^
Paul Blum, ed. (1 April 2008). Archaea: New Models for Prokaryotic Biology. Caister Academic Press. ISBN 978-1-904455-27-1.
- ^ Brown, Mark (7 September 2011). "The Earth's most precious metals arrived on meteorites". wired.co.uk.
- PMID 16168748.
- PMID 26164860.
- PMID 27855621.
- PMID 16343746.
- ISBN 978-0-8247-0765-1.
- ^ 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.
- PMID 9144946.
- ^ "CDC – NIOSH Pocket Guide to Chemical Hazards – Tungsten". www.cdc.gov. Archived from the original on 2015-11-25. Retrieved 2015-11-24.
- ^ "Google Trends". Google Trends. Retrieved 2023-12-08.
External links
- 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 Archived 2010-03-18 at the Wayback Machine
- Elementymology & Elements Multidict by Peter van der Krogt – Tungsten
- Official website of the International Tungsten Industry Association