Tungsten

Tungsten (also called wolfram)^[11][12] is a chemical element; it has symbol W and atomic number 74. It is a rare metal found naturally on Earth almost exclusively as compounds with other elements. It was identified as a new element in 1781 and first isolated as a metal in 1783. Its important ores include scheelite and wolframite, the latter lending the element its alternative name.

This article is about the chemical element. For other uses, see Tungsten (disambiguation).

Tungsten, ₇₄W

Tungsten
Pronunciation	/ˈtʌŋstən/ ​(TUNG-stən)
Alternative name	Wolfram, pronounced: /ˈwʊlfrəm/ (WUUL-frəm)
Allotropes	α-tungsten (common), β-tungsten
Appearance	Grayish white, lustrous
Standard atomic weight Ar°(W)
	183.84±0.01[1] 183.84±0.01 (abridged)[2]
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 ↑ W ↓ Sg tantalum ← tungsten → rhenium
Atomic number (Z)	74
Group	group 6
Period	period 6
Block	d-block
Electron configuration	[Xe] 4f14 5d4 6s2[3]
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 (at 20° C)	19.254 g/cm3 [4]
when liquid (at m.p.)	17.6 g/cm3
Heat of fusion	52.31 kJ/mol[5][6]
Heat of vaporization	774 kJ/mol
Molar heat capacity	24.27 J/(mol·K)
Vapor pressure P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 3477 3773 4137 4579 5127 5823
Atomic properties
Oxidation states	−4, −2, −1, 0, +1, +2, +3, +4, +5, +6 (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 of tungsten
Other properties
Natural occurrence	primordial
Crystal structure	​body-centered cubic (bcc) (cI2)
Lattice constant	a = 316.52 pm (at 20 °C)[4]
Thermal expansion	4.42×10−6/K (at 20 °C)[4]
Thermal conductivity	173 W/(m⋅K)
Electrical resistivity	52.8 nΩ⋅m (at 20 °C)
Magnetic ordering	paramagnetic[7]
Molar magnetic susceptibility	+59.0×10−6 cm3/mol (298 K)[8]
Young's modulus	411 GPa
Shear modulus	161 GPa
Bulk modulus	310 GPa
Speed of sound thin rod	4620 m/s (at r.t.) (annealed)
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 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 v e
Main isotopes Decay abun­dance half-life (t1/2) mode pro­duct 180W 0.120% 1.8×1018 y α 176Hf 181W synth 121.2 d ε 181Ta 182W 26.5% stable 183W 14.3% stable 184W 30.6% stable 185W synth 75.1 d β− 185Re 186W 28.4% stable 188W synth 69.78 d β− 188Re
Category: Tungsten view talk edit | references

The free element is remarkable for its robustness, especially the fact that it has the highest melting point of all known elements, melting at 3,422 °C (6,192 °F; 3,695 K). It also has the highest boiling point, at 5,930 °C (10,706 °F; 6,203 K).^[13] Its density is 19.254 g/cm³,^[4] comparable with that of uranium and gold, and much higher (about 1.7 times) than that of lead.^[14] Polycrystalline tungsten is an intrinsically brittle^[15][16][17] and hard material (under standard conditions, when uncombined), making it difficult to work into metal. However, pure single-crystalline tungsten is more ductile and can be cut with a hard-steel hacksaw.^[18]

Tungsten occurs in many alloys, which have numerous applications, including incandescent light bulb filaments, X-ray tubes, electrodes in gas tungsten arc welding, superalloys, and radiation shielding. Tungsten's hardness and high density make it suitable for military applications in penetrating projectiles. Tungsten compounds are often used as industrial catalysts. Its largest use is in tungsten carbide, a wear-resistant metal used in metalworking, mining, and construction.^[19] About 50% of tungsten is used in tungsten carbide, with the remaining major use being alloys and steels: less than 10% is used other compounds.^[20]

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.^[21][22]

Characteristics

Physical properties

In its raw form, tungsten is a hard steel-grey metal that is often brittle and hard to work. Purified, monocrystalline tungsten retains its hardness (which exceeds that of many steels), and becomes malleable enough that it can be worked easily.^[18] It is worked by forging, drawing, or extruding but it is more commonly formed by sintering.

Of all metals in pure form, tungsten has the highest melting point (3,422 °C, 6,192 °F), lowest vapor pressure (at temperatures above 1,650 °C, 3,000 °F), and the highest tensile strength.^[23] Although carbon remains solid at higher temperatures than tungsten, carbon sublimes at atmospheric pressure instead of melting, so it has no melting point. Moreover, tungsten's most stable crystal phase does not exhibit any high-pressure-induced structural transformations for pressures up to at least 364 gigapascals.^[24] 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.^[25] Alloying small quantities of tungsten with steel greatly increases its toughness.^[14]

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^[26] and a much lower superconducting transition temperature T_C relative to the β phase: ca. 0.015 K vs. 1–4 K; mixing the two phases allows obtaining intermediate T_C values.^[27][28] The T_C value can also be raised by alloying tungsten with another metal (e.g. 7.9 K for W-Tc).^[29] Such tungsten alloys are sometimes used in low-temperature superconducting circuits.^[30][31][32]

Isotopes

Main article: Isotopes of tungsten

Naturally occurring tungsten consists of four stable isotopes (¹⁸²W, ¹⁸³W, ¹⁸⁴W, and ¹⁸⁶W) and one very long-lived radioisotope, ¹⁸⁰W. Theoretically, all five can decay into isotopes of element 72 (hafnium) by alpha emission, but only ¹⁸⁰W has been observed to do so, with a half-life of (1.8±0.2)×10¹⁸ years;^[33][34] on average, this yields about two alpha decays of ¹⁸⁰W per gram of natural tungsten per year.^[35] This rate is equivalent to a specific activity of roughly 63 micro-becquerel per kilogram. This rate of decay is orders of magnitude lower than that observed in carbon or potassium as found on earth, which likewise contain small amounts of long-lived radioactive isotopes. Bismuth was long thought to be non-radioactive, but ²⁰⁹
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 radioisotopes of tungsten have been characterized, the most stable of which are ¹⁸¹W with a half-life of 121.2 days, ¹⁸⁵W with a half-life of 75.1 days, ¹⁸⁸W with a half-life of 69.4 days, ¹⁷⁸W with a half-life of 21.6 days, and ¹⁸⁷W with a half-life of 23.72 h.^[35] All of the remaining radioactive isotopes have half-lives of less than 3 hours, and most of these have half-lives below 8 minutes.^[35] Tungsten also has 11 meta states, with the most stable being ^179mW (t_1/2 6.4 minutes).

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 trioxide compound tungsten(VI), WO₃. It will, however, react directly with fluorine (F₂) at room temperature to form tungsten(VI) fluoride (WF₆), a colorless gas. At around 250 °C it will react with chlorine or bromine, and under certain hot conditions will react with iodine. Finely divided tungsten is pyrophoric.^[36][37]

The most common formal oxidation state of tungsten is +6, but it exhibits all oxidation states from −2 to +6.^[37][38] 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 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
₁₂O¹⁰⁻
₄₂.^[39] 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 H₃PW₁₂O₄₀.

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 sextuple bond between tungsten atoms — the highest known bond order among stable atoms.^[40][41]

History

In 1781, Carl Wilhelm Scheele discovered that a new acid, tungstic acid, could be made from scheelite (at the time called tungsten).^[42][43] Scheele and Torbern Bergman suggested that it might be possible to obtain a new metal by reducing this acid.^[44] 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").^{[45][46][47][48][49]}

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.^[50] 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,^[51][52] 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.^[53][54][55]

It is suggested that remnants of wolfram have been found in what may have been the garden of the astronomer/alchemist Tycho Brahe^[56]

Etymology

The name tungsten (which means 'heavy stone' in Swedish and was the old Swedish name for the mineral scheelite and other minerals of similar density) is used in English, French, and many other languages as the name of the element, but 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.^[18] The name wolframite is derived from German wolf rahm ('wolf soot, wolf cream'), the name given to tungsten by Johan Gottschalk Wallerius in 1747. This, in turn, derives from Latin lupi spuma, the name Georg Agricola used for the mineral 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, as though the mineral devoured it like a wolf.^[10] This naming follows a tradition of colorful names miners from the Ore Mountains would give various minerals, out of a superstition that certain ones that looked as if they contained then-known valuable metals but when extracted were somehow "hexed". Cobalt (cf. Kobold), pitchblende (cf. German blenden for 'to blind, to deceive') and nickel (cf. "Old Nick") derive their names from the same miners' idiom.

Occurrence

Wolframite mineral, with a scale in cm

Tungsten has thus far not been found in nature in its pure form.^[57] Instead, tungsten is found mainly in the minerals wolframite and scheelite.^[57] 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

See also: Category:Tungsten compounds

Structure of W₆Cl₁₈ ("tungsten trichloride")

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 metal clusters, and very low oxidation states are typically associated with CO complexes. The chemistries of tungsten and molybdenum show strong similarities to each other, as well as contrasts with their lighter congener, chromium. The relative rarity of tungsten(III), for example, contrasts with the pervasiveness of the chromium(III) compounds. The highest oxidation state is seen in tungsten(VI) oxide (WO₃).^[58] Tungsten(VI) oxide is soluble in aqueous base, forming tungstate (WO₄²⁻). This oxyanion condenses at lower pH values, forming polyoxotungstates.^[59]

The broad range of oxidation states of tungsten is reflected in its various chlorides:^[58]

• 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) chloride WCl₆, which contrasts with the instability of MoCl₆.

Organotungsten compounds are numerous and also span a range of oxidation states. Notable examples include the trigonal prismatic W(CH₃)₆ and octahedral W(CO)₆.

Production

Tungsten mining in Rwanda forms an important part of the country's economy.^{[citation needed]}

Tungsten concentrate production, 1946

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),^[60] 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.^[61]

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.^[62]

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. Following increases in tungsten prices, this mine was reactivated in 2014,^[63] but ceased activities in 2018.^[64]

Within the EU, the Austrian Felbertal scheelite deposit is one of the few producing tungsten mines.^[65] 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.^[66]

Tungsten is considered to be a conflict mineral due to the unethical mining practices observed in the Democratic Republic of the Congo.^[67][68]

South Korea's Sangdong mine, one of the world's largest tungsten mines with 7,890,000 tonnes of high-grade tungsten reportedly buried, was closed in 1994 due to low profitability but has since re-registered mining rights and is scheduled to resume activities in 2024.^[69][70]

Extraction

Tungsten is extracted from its ores in several stages. The ore is eventually converted to tungsten(VI) oxide (WO₃), which is heated with hydrogen or carbon to produce powdered tungsten.^[44] 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 WF₆:

WF₆ + 3 H₂ → W + 6 HF

or pyrolytic decomposition:^[71]

WF₆ → W + 3 F₂ (ΔH_r = +)

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.^[72] The prices are usually quoted for tungsten concentrate or WO₃.^[61]

Applications

Close-up of a tungsten filament inside a halogen lamp

Tungsten carbide jewelry

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.^[20] Because of the high ductile-brittle transition temperature of tungsten, its products are conventionally manufactured through powder metallurgy, spark plasma sintering, chemical vapor deposition, hot isostatic pressing, and thermoplastic routes. A more flexible manufacturing alternative is selective laser melting, which is a form of 3D printing and allows creating complex three-dimensional shapes.^[73]

Industrial

Tungsten is mainly used in the production of hard materials based on tungsten carbide (WC), one of the hardest carbides. WC is an efficient electrical conductor, but W₂C is less so. WC is used to make wear-resistant abrasives, and "carbide" cutting tools such as knives, drills, circular saws, dies, milling and turning tools used by the metalworking, woodworking, mining, petroleum and construction industries.^[14] 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.^[74]

The jewelry industry makes rings of sintered tungsten carbide, tungsten carbide/metal composites, and also metallic tungsten.^[75] 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.^[76] 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.^[77]

Alloys

Further information: Tantalum–tungsten alloys

The hardness and heat resistance of tungsten can contribute to useful alloys. A good example is high-speed steel, which can contain as much as 18% tungsten.^[78] 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.^[79] Tungsten alloys are used in a wide range of applications, including the aerospace and automotive industries and radiation shielding.^[80] Superalloys containing tungsten, such as Hastelloy and Stellite, are used in turbine 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.^[81]

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 nickel, 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 desired (for example, in ordinary small arms bullets designed to penetrate body armor). Similarly, tungsten alloys have also been used in 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 bore 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, caused in part by the Wolfram Crisis, limited their use.^{[citation needed]}

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.^[82]

Chemical applications

Tungsten(IV) sulfide is a high temperature lubricant and is a component of catalysts for hydrodesulfurization.^[83] MoS₂ is more commonly used for such applications.^[84]

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.^[23] Tungsten oxide (WO₃) is incorporated into selective catalytic reduction (SCR) catalysts found in coal-fired power plants. These catalysts convert nitrogen oxides (NO_x) to nitrogen (N₂) and water (H₂O) using ammonia (NH₃). The tungsten oxide helps with the physical strength of the catalyst and extends catalyst life.^[85] Tungsten containing catalysts are promising for epoxidation,^[86] oxidation,^[87] and hydrogenolysis reactions.^[88] Tungsten heteropoly acids are key component of multifunctional catalysts.^[89] Tungstates can be used as photocatalyst,^[90] while the tungsten sulfide as electrocatalyst.^[91]

Niche uses

Applications requiring its high density include weights, counterweights, ballast keels for yachts, tail ballast for commercial aircraft, rotor weights for civil and military helicopters, and as ballast in race cars for NASCAR and Formula One.^[92] Being slightly less than twice the density, tungsten is seen as an alternative (albeit more expensive) to lead fishing sinkers. 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^[93] (to allow for a smaller diameter and thus tighter groupings) or for artificial flies (tungsten beads allow the fly to sink rapidly). Tungsten is also used as a heavy bolt to lower the rate of fire of the SWD M11/9 sub-machine gun from 1300 RPM to 700 RPM. Tungsten has seen use recently in nozzles for 3D printing; the high wear resistance and thermal conductivity of tungsten carbide improves the printing of abrasive filaments.^[94] Some string instrument strings incorporates tungsten.^[95][96] Tungsten is used as an absorber on the electron telescope on the Cosmic Ray System of the two Voyager spacecraft.^[97]

Gold substitution

Its density, similar to that of gold, allows tungsten to be used in jewelry as an alternative to gold or platinum.^[18][98] 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), and its price of the order of one-thousandth, tungsten can also be used in counterfeiting of gold bars, such as by plating a tungsten bar with gold,^{[99][100][101]} which has been observed since the 1980s,^[102] or taking an existing gold bar, drilling holes, and replacing the removed gold with tungsten rods.^[103] The densities are not exactly the same, and other properties of gold and tungsten differ, but gold-plated tungsten will pass superficial tests.^[99]

Gold-plated tungsten is available commercially from China (the main source of tungsten), both in jewelry and as bars.^[104]

Electronics

Because it retains its strength at high temperatures and has a high melting point, elemental tungsten is used in many high-temperature applications,^[105] 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).^[106]

Tungsten electrode used in a gas tungsten arc welding torch

Tungsten filament is used in incandescent lightbulbs, where it is heated until it glows

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.^[71]

The electronic structure of tungsten makes it one of the main sources for X-ray targets,^[107][108] 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.^[23] In addition to its high melting point, when tungsten is doped with potassium, it leads to an increased shape stability (compared with non-doped tungsten). This ensures that the filament does not sag, and no undesired changes occur.^[109]

Tungsten is used in producing vibration motors, also known as mobile vibrators.^[110] These motors are integral components that provide tactile feedback to users, alerting them to incoming calls, messages, and notifications.^[111] Tungsten’s high density, hardness, and wear resistance property helps to endure the high-speed rotational vibrations these motors generate.^[112][113]

Nanowires

Through top-down nanofabrication processes, tungsten nanowires have been fabricated and studied since 2002.^[114] 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.^[115] Such tungsten nanowires have potential applications in nanoelectronics and importantly as pH probes and gas sensors.^[116] 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.^[117] Using the Deal–Grove model it is possible to predict the oxidation kinetics of nanowires fabricated through such thermal oxidation processing.^[118]

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,^[119] 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 archaea,^[120] 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.^[121] 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 molybdopterin-requiring enzymes.^[122] 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.^[123] 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.^[124] 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.^[125]

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.^[126] The soil's chemistry determines how the tungsten polymerizes; alkaline soils cause monomeric tungstates; acidic soils cause polymeric tungstates.^[127]

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.^[128]

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 [zh] salts may be used as biological copper chelation chemicals, similar to the tetrathiomolybdates.^[129]

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^[130]

Health factors

Because tungsten is a rare metal^[131] and its compounds are generally inert, the effects of tungsten on the environment are limited.^[132] The abundance of tungsten in the Earth's crust is thought to be about 1.5 parts per million. It is the 58th most abundant element found on Earth.^[133]

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.^[134][135] The median lethal dose LD₅₀ depends strongly on the animal and the method of administration and varies between 59 mg/kg (intravenous, rabbits)^[136][137] and 5000 mg/kg (tungsten metal powder, intraperitoneal, rats).^[138][139]

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.^[140]

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.^[141]

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

1. "Standard Atomic Weights: Tungsten". CIAAW. 1991.
2. Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
3. Berger, Dan. "Why does Tungsten not 'Kick' up an electron from the s sublevel ?". Bluffton College, USA.
4. Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. ISBN 978-1-62708-155-9.
5. Lide, David R., ed. (2009). CRC Handbook of Chemistry and Physics (90th ed.). Boca Raton, Florida: CRC Press. p. 6-134. ISBN 978-1-4200-9084-0.
6. Tolias P. (2017). "Analytical expressions for thermophysical properties of solid and liquid tungsten relevant for fusion applications". Nuclear Materials and Energy. 13: 42–57. arXiv:1703.06302. Bibcode:2017arXiv170306302T. doi:10.1016/j.nme.2017.08.002. S2CID 99610871.
7. Lide, D. R., ed. (2005). "Magnetic susceptibility of the elements and inorganic compounds" (PDF). CRC Handbook of Chemistry and Physics (86th ed.). Boca Raton (FL): CRC Press. ISBN 978-0-8493-0486-6. Archived from the original (PDF) on 2011-03-03.
8. Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. p. E110. ISBN 978-0-8493-0464-4.
9. "Tungsten". Royal Society of Chemistry. Royal Society of Chemistry. Retrieved May 2, 2020.
10. van der Krogt, Peter. "Wolframium Wolfram Tungsten". Elementymology& Elements Multidict. Archived from the original on 2010-01-23. Retrieved 2010-03-11.
11. "wolfram" on Merriam-Webster.
12. "wolfram" on Oxford Dictionaries.
13. Zhang Y; Evans JRG and Zhang S (January 2011). "Corrected Values for Boiling Points and Enthalpies of Vaporization of Elements in Handbooks". J. Chem. Eng. Data. 56 (2): 328–337. doi:10.1021/je1011086.{{cite journal}}: CS1 maint: multiple names: authors list (link)
14. Daintith, John (2005). Facts on File Dictionary of Chemistry (4th ed.). New York: Checkmark Books. ISBN 978-0-8160-5649-1.
15. Lassner, Erik; Schubert, Wolf-Dieter (1999). "low temperature brittleness". Tungsten: properties, chemistry, technology of the element, alloys, and chemical compounds. Springer. pp. 20–21. ISBN 978-0-306-45053-2.
16. Prakash, C.; Lee, H.; Alucozai, M.; Tomar, V. (2016). "An analysis of the influence of grain boundary strength on microstructure dependent fracture in polycrystalline tungsten". International Journal of Fracture. 199: 1–20. doi:10.1007/s10704-016-0083-0. S2CID 137928096.
17. Gludovatz, B.; Wurster, S.; Weingärtner, T.; Hoffmann, A.; Pippan, R. (2011). "Influence of impurities on the fracture behavior of tungsten". Philosophical Magazine (Submitted manuscript). 91 (22): 3006–3020. Bibcode:2011PMag...91.3006G. doi:10.1080/14786435.2011.558861. S2CID 137145004.
18. Stwertka, Albert (2002). A Guide to the elements (2nd ed.). New York: Oxford University Press. ISBN 978-0-19-515026-1.
19. "Tungsten Statistics and Information". National Minerals Information Center. U.S. Geological Survey. 2024. Retrieved 2024-07-04.
20. Erik Lassner, Wolf-Dieter Schubert, Eberhard Lüderitz, Hans Uwe Wolf, "Tungsten, Tungsten Alloys, and Tungsten Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim. doi:10.1002/14356007.a27_229.
21. McMaster, J. & Enemark, John H. (1998). "The active sites of molybdenum- and tungsten-containing enzymes". Current Opinion in Chemical Biology. 2 (2): 201–207. doi:10.1016/S1367-5931(98)80061-6. PMID 9667924.
22. Hille, Russ (2002). "Molybdenum and tungsten in biology". Trends in Biochemical Sciences. 27 (7): 360–367. doi:10.1016/S0968-0004(02)02107-2. PMID 12114025.
23. Hammond, C. R. (2004). The Elements, in Handbook of Chemistry and Physics (81st ed.). CRC press. ISBN 978-0-8493-0485-9.
24. McMahon, Malcolm I.; Nelmes, Richard J. (2006). "High-pressure structures and phase transformations in elemental metals". Chemical Society Reviews. 35 (10): 943–963. doi:10.1039/b517777b. ISSN 0306-0012. PMID 17003900.
25. Lassner, Erik; Schubert, Wolf-Dieter (1999). Tungsten: properties, chemistry, technology of the element, alloys, and chemical compounds. Springer. p. 9. ISBN 978-0-306-45053-2.
26. Bean, Heather (October 19, 1998). Material Properties and Analysis Techniques for Tungsten Thin Films. frii.com
27. Lita, A. E.; Rosenberg, D.; Nam, S.; Miller, A.; Balzar, D.; Kaatz, L. M.; Schwall, R. E. (2005). "Tuning of Tungsten Thin Film Superconducting Transition Temperature for Fabrication of Photon Number Resolving Detectors" (PDF). IEEE Transactions on Applied Superconductivity. 15 (2): 3528–3531. Bibcode:2005ITAS...15.3528L. doi:10.1109/TASC.2005.849033. S2CID 5804011. Archived (PDF) from the original on 2013-05-13.
28. Johnson, R. T.; O. E. Vilches; J. C. Wheatley; Suso Gygax (1966). "Superconductivity of Tungsten". Physical Review Letters. 16 (3): 101–104. Bibcode:1966PhRvL..16..101J. doi:10.1103/PhysRevLett.16.101.
29. Autler, S. H.; J. K. Hulm; R. S. Kemper (1965). "Superconducting Technetium–Tungsten Alloys". Physical Review. 140 (4A): A1177–A1180. Bibcode:1965PhRv..140.1177A. doi:10.1103/PhysRev.140.A1177.
30. Shailos, A.; W Nativel; A Kasumov; C Collet; M Ferrier; S Guéron; R Deblock; H Bouchiat (2007). "Proximity effect and multiple Andreev reflections in few-layer graphene". Europhysics Letters (EPL). 79 (5): 57008. arXiv:cond-mat/0612058. Bibcode:2007EL.....7957008S. doi:10.1209/0295-5075/79/57008. S2CID 119351442.
31. Kasumov, A. Yu.; K. Tsukagoshi; M. Kawamura; T. Kobayashi; Y. Aoyagi; K. Senba; T. Kodama; H. Nishikawa; I. Ikemoto; K. Kikuchi; V. T. Volkov; Yu. A. Kasumov; R. Deblock; S. Guéron; H. Bouchiat (2005). "Proximity effect in a superconductor-metallofullerene-superconductor molecular junction". Physical Review B. 72 (3): 033414. arXiv:cond-mat/0402312. Bibcode:2005PhRvB..72c3414K. doi:10.1103/PhysRevB.72.033414. S2CID 54624704.
32. Kirk, M. D.; D. P. E. Smith; D. B. Mitzi; J. Z. Sun; D. J. Webb; K. Char; M. R. Hahn; M. Naito; B. Oh; M. R. Beasley; T. H. Geballe; R. H. Hammond; A. Kapitulnik; C. F. Quate (1987). "Point-contact electron tunneling into the high-T_{c} superconductor Y-Ba-Cu-O". Physical Review B. 35 (16): 8850–8852. Bibcode:1987PhRvB..35.8850K. doi:10.1103/PhysRevB.35.8850. PMID 9941272.
33. Danevich, F. A.; et al. (2003). "α activity of natural tungsten isotopes". Phys. Rev. C. 67 (1): 014310. arXiv:nucl-ex/0211013. Bibcode:2003PhRvC..67a4310D. doi:10.1103/PhysRevC.67.014310. S2CID 6733875.
34. Cozzini, C.; et al. (2004). "Detection of the natural α decay of tungsten". Phys. Rev. C. 70 (6): 064606. arXiv:nucl-ex/0408006. Bibcode:2004PhRvC..70f4606C. doi:10.1103/PhysRevC.70.064606. S2CID 118891861.
35. 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.
36. "Tungsten: reactions of elements".
37. Emsley, John E. (1991). The elements (2nd ed.). New York: Oxford University Press. ISBN 978-0-19-855569-8.
38. Morse, P. M.; Shelby, Q. D.; Kim, D. Y.; Girolami, G. S. (2008). "Ethylene Complexes of the Early Transition Metals: Crystal Structures of [HfEt₄(C₂H₄)²⁻] and the Negative-Oxidation-State Species [TaHEt(C₂H₄)₃³⁻] and [WH(C₂H₄)₄³⁻]". Organometallics. 27 (5): 984–993. doi:10.1021/om701189e.
39. Smith, Bradley J.; Patrick, Vincent A. (2000). "Quantitative Determination of Sodium Metatungstate Speciation by 183W N.M.R. Spectroscopy". Australian Journal of Chemistry. 53 (12): 965. doi:10.1071/CH00140.
40. Borin, Antonio Carlos; Gobbo, João Paulo; Roos, Björn O. (January 2008). "A theoretical study of the binding and electronic spectrum of the Mo2 molecule". Chemical Physics. 343 (2–3): 210–216. Bibcode:2008CP....343..210B. doi:10.1016/j.chemphys.2007.05.028. ISSN 0301-0104.
41. Roos, Björn O.; Borin, Antonio C.; Laura Gagliardi (2007). "Reaching the Maximum Multiplicity of the Covalent Chemical Bond". Angew. Chem. Int. Ed. 46 (9): 1469–72. doi:10.1002/anie.200603600. PMID 17225237.
42. 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).
43. 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).
44. Saunders, Nigel (2004). Tungsten and the Elements of Groups 3 to 7 (The Periodic Table). Chicago, Illinois: Heinemann Library. ISBN 978-1-4034-3518-7.
45. "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)
46. "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)
47. 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.
48. 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).
49. 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
50. Watson, Greig (2014-06-06). "Vital WW1 metal 'in enemy hands'". BBC News. Retrieved 2018-02-10.
51. Stevens, Donald G. (1999). "World War II Economic Warfare: The United States, Britain, and Portuguese Wolfram". The Historian. 61 (3): 539. doi:10.1111/j.1540-6563.1999.tb01036.x.
52. Wheeler, L. Douglas (Summer 1986). "The Price of Neutrality: Portugal, the Wolfram Question, and World War II". Luso-Brazilian Review. 23 (1): 107–127. JSTOR 3513391.
53. General Electric Co. v. De Forest Radio Co., 28 F.2d 641, 643 (3rd Cir. 1928)
54. Guruswamy, Lakshman D.; McNeely, Jeffrey A. (1998). Protection of global biodiversity: converging strategies. Duke University Press. pp. 333–. ISBN 978-0-8223-2188-0.
55. General Electric Co. v. De Forest Radio Co., 28 F.2d 641 (3d Cir. 1928).
56. Physics Journal report (24 July 2024):Chemical analyses find hidden elements from renaissance astronomer Tycho Brahe's alchemy laboratory
57. "Tungsten, W, atomic number 74". Institute of rare earths elements and strategic metals.
58. Holleman, Arnold F.; Wiberg, Egon; Wiberg, Nils (1985). "Mangan". Lehrbuch der Anorganischen Chemie (in German) (91–100 ed.). Walter de Gruyter. pp. 1110–1117. ISBN 978-3-11-007511-3.
59. Pope, Michael T.; Müller, Achim (1997). "Polyoxometalate Chemistry: An Old Field with New Dimensions in Several Disciplines". Angewandte Chemie International Edition. 30: 34–48. doi:10.1002/anie.199100341.
60. Tungsten. Mineral Commodity Summaries. USGS (2017)
61. Shedd, Kim B. (December 2018) Tungsten. 2016 Minerals Yearbook. USGS
62. Tungsten. Mineral Commodity Summaries. USGS (2018)
63. "Work starts on £130m Devon tungsten mine". BBC News. 9 June 2014. Archived from the original on 2014-12-05.
64. "How Hemerdon mine lost £100m in just three years". Plymouth Herald. 12 October 2018. Retrieved 24 January 2019.
65. Altenberger, Florian; Raith, Johann G.; Weilbold, Julia; Auer, Christian; Knoll, Tanja; Paulick, Holger; Schedl, Albert; Aupers, Karsten; Schmidt, Steffen; Neinavaie, Hassan (2021-05-07). "Casting new light on tungsten deposits in the Eastern Alps". Zeitschrift der Deutschen Gesellschaft für Geowissenschaften. 172: 63–72. doi:10.1127/zdgg/2021/0262. S2CID 233912162.
66. Mateus, António; Lopes, Catarina; Martins, Luís; Gonçalves, Mário Abel (June 2021). "Current and Foreseen Tungsten Production in Portugal, and the Need of Safeguarding the Access to Relevant Known Resources". Resources. 10 (6): 64. doi:10.3390/resources10060064. hdl:10451/53675. ISSN 2079-9276.
67. Kristof, Nicholas D. (2010-06-27). "Death by Gadget". The New York Times. Archived from the original on 2016-08-31.
68. "The Genocide Behind Your Smart Phone". The Daily Beast. July 16, 2010. Archived from the original on 2011-11-17.
69. "Project Technical Reports – Sangdong Reserves/Resources NI 43-101" (PDF). Almonty Industries. 31 July 2016. Archived from the original (PDF) on 12 September 2024. Retrieved 12 September 2024.
70. "Almonty advances Sangdong tungsten mine in South Korea". The Northern Miner. 2 August 2023. Archived from the original on 28 April 2024. Retrieved 28 April 2024.
71. Schey, John A. (1987). Introduction to Manufacturing Processes (2nd ed.). McGraw-Hill, Inc.
72. "Tungsten Pricing". International Tungsten Industry Association. Retrieved 18 June 2020.
73. Tan, C. (2018). "Selective laser melting of high-performance pure tungsten: parameter design, densification behavior and mechanical properties". Sci. Technol. Adv. Mater. 19 (1): 370–380. Bibcode:2018STAdM..19..370T. doi:10.1080/14686996.2018.1455154. PMC 5917440. PMID 29707073.
74. Don Law-West; Louis Perron. "Tungsten". The Canadian Encyclopaedia. Retrieved 2020-07-18.
75. Tungsten: The Element, History, Uses and Wedding Bands.tungstenworld.com
76. de Laubenfels, Blair; Weber, Christy; Bamberg, Kim (2009). Knack Planning Your Wedding: A Step-by-Step Guide to Creating Your Perfect Day. Globe Pequot. pp. 35–. ISBN 978-1-59921-397-2.
77. Schultz, Ken (2009). Ken Schultz's Essentials of Fishing: The Only Guide You Need to Catch Freshwater and Saltwater Fish. John Wiley and Sons. pp. 138–. ISBN 978-0-470-44431-3.
78. "Tungsten Applications – Steel". Azom. 2000–2008. Archived from the original on 2008-08-15. Retrieved 2008-06-18.
79. Ramakrishnan, P. (2007). "Powder metallurgy for Aerospace Applications". Powder Metallurgy: Processing for automotive, electrical / electronic, and engineering industry. New Age International. p. 38. ISBN 978-81-224-2030-2.
80. "Tungsten Applications". wolfmet.com. Archived from the original on 2013-09-01.
81. "TIG Torches & TIG Torch Parts". AES Industrial Supplies Limited. Retrieved 2021-05-06.
82. Dense Inert Metal Explosive (DIME). Defense-update.com. Retrieved on 2011-08-07.
83. Delmon, Bernard & Froment, Gilbert F. (1999). Hydrotreatment and hydrocracking of oil fractions: proceedings of the 2nd international symposium, 7th European workshop, Antwerpen, Belgium, November 14–17, 1999. Elsevier. pp. 351–. ISBN 978-0-444-50214-8. Retrieved 18 December 2011.
84. Mang, Theo & Dresel, Wilfried (2007). Lubricants and Lubrication. John Wiley & Sons. pp. 695–. ISBN 978-3-527-61033-4.
85. Spivey, James J. (2002). Catalysis. Royal Society of Chemistry. pp. 239–. ISBN 978-0-85404-224-1. Retrieved 18 December 2011.
86. Lewandowski, Grzegorz; Kujbida, Marcin; Wróblewska, Agnieszka (1 April 2021). "Epoxidation of 1,5,9-cyclododecatriene with hydrogen peroxide under phase-transfer catalysis conditions: influence of selected parameters on the course of epoxidation". Reaction Kinetics, Mechanisms and Catalysis. 132 (2): 983–1001. doi:10.1007/s11144-021-01960-7. ISSN 1878-5204.
87. Kinetic studies of propane oxidation on Mo and V based mixed oxide catalysts. 2011. pp. 165–170.
88. Liu, Lujie; Asano, Takehiro; Nakagawa, Yoshinao; Gu, Minyan; Li, Congcong; Tamura, Masazumi; Tomishige, Keiichi (5 September 2021). "Structure and performance relationship of silica-supported platinum–tungsten catalysts in selective C-O hydrogenolysis of glycerol and 1,4-anhydroerythritol". Applied Catalysis B: Environmental. 292: 120164. Bibcode:2021AppCB.29220164L. doi:10.1016/j.apcatb.2021.120164.
89. Kornas, A.; Śliwa, M.; Ruggiero-Mikołajczyk, M.; Samson, K.; Podobiński, J.; Karcz, R.; Duraczyńska, D.; Rutkowska-Zbik, D.; Grabowski, R. (1 June 2020). "Direct hydrogenation of CO2 to dimethyl ether (DME) over hybrid catalysts containing CuO/ZrO2 as a metallic function and heteropolyacids as an acidic function". Reaction Kinetics, Mechanisms and Catalysis. 130 (1): 179–194. doi:10.1007/s11144-020-01778-9. ISSN 1878-5204.
90. Campos, Willison E. O.; Lopes, Anna S. C.; Monteiro, Waldinei R.; Filho, Geraldo N. R.; Nobre, Francisco X.; Luz, Patrícia T. S.; Nascimento, Luís A. S.; Costa, Carlos E. F.; Monteiro, Wesley F.; Vieira, Michele O.; Zamian, José R. (1 October 2020). "Layered double hydroxides as heterostructure LDH@Bi2WO6 oriented toward visible-light-driven applications: synthesis, characterization, and its photocatalytic properties". Reaction Kinetics, Mechanisms and Catalysis. 131 (1): 505–524. doi:10.1007/s11144-020-01830-8. ISSN 1878-5204. S2CID 220948033.
91. Maslana, K.; Wenelska, K.; Biegun, M.; Mijowska, E. (5 June 2020). "High catalytic performance of tungsten disulphide rodes in oxygen evolution reactions in alkaline solutions". Applied Catalysis B: Environmental. 266: 118575. Bibcode:2020AppCB.26618575M. doi:10.1016/j.apcatb.2019.118575. S2CID 213246090.
92. "F1 Technique: The secrets of ballast in a Formula 1 car". Auto123.com. 2013-12-25. Retrieved 2019-02-03.
93. Turrell, Kerry (2004). Tungsten. Marshall Cavendish. p. 24. ISBN 978-0-7614-1548-0.
94. Duchaine, Simon (2018-03-09). "The Tungsten Carbide Nozzle Offers a Balance Between Wear Resistance and High Performance". 3dprint.com. Retrieved 2018-10-23.
95. Prieto, Carlos (2011-02-01). The Adventures of a Cello. Austin: University of Texas Press. p. 10. ISBN 978-0-292-72393-1.
96. 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)
97. "CRS Instruments". NASA. Archived from the original on 2017-02-01.
98. Hesse, Rayner W. (2007). "tungsten". Jewelrymaking through history: an encyclopedia. Westport, Conn.: Greenwood Press. pp. 190–192. ISBN 978-0-313-33507-5.
99. 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.
100. "Zinc Dimes, Tungsten Gold & Lost Respect Archived 2011-10-08 at the Wayback Machine", Jim Willie, Nov 18 2009
101. "Largest Private Refinery Discovers Gold-Plated Tungsten Bar – Coin Update". news.coinupdate.com.
102. "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.
103. Tungsten filled Gold bars Archived 2012-03-26 at the Wayback Machine, ABC Bullion, Thursday, March 22, 2012
104. Tungsten Alloy for Gold Substitution Archived 2012-03-22 at the Wayback Machine, China Tungsten
105. DeGarmo, E. Paul (1979). Materials and Processes in Manufacturing (5th ed.). New York: MacMillan Publishing.
106. Cary, Hoawrd B.; Helzer, Scott (2005). Modern welding technology. 978-0-13-113029-6.: Upper Saddle River. ISBN 978-0-13-113029-6.{{cite book}}: CS1 maint: location (link)
107. Curry, Thomas S.; Dowdey, James E.; Murry, Robert C.; Christensen, Edward E. (1990-08-01). Christensen's physics of diagnostic radiology. Lippincott Williams & Wilkins. pp. 29–35. ISBN 978-0-8121-1310-5. Archived from the original on 2017-11-11.
108. Hasz, Wayne Charles et al. (August 6, 2002) "X-ray target" U.S. patent 6,428,904
109. "Non-Sag Doped Tungsten – Union City Filament". Union City Filament. Archived from the original on 2017-05-01. Retrieved 2017-04-28.
110. Trento, Chin (Mar 8, 2024). "How Much Gold Can an iPhone Refine?". Stanford Advanced Materials. Retrieved June 26, 2024.
111. US patent 8558677B2, S. Stephen, "Tactile alerting mechanism for portable communications device", published Oct 10, 2013
112. Nissen, Nils F.; Reinhold, Julia (2021). "Recyclability of Tungsten, Tantalum and Neodymium from Smartphones". In Inoue, M.; Fukushige, S. (eds.). EcoDesign and Sustainability I: Products, Services, and Business Models. Springer Singapore. pp. 365–381. ISBN 978-981-15-6779-7.
113. Micallef, Christian; Zhuk, Yuri (2020). "Recent Progress in Precision Machining and Surface Finishing of Tungsten Carbide Hard Composite Coatings". Coatings. 10 (8): 731. doi:10.3390/coatings10080731.
114. Li Yadong (2002). "From Surfactant–Inorganic Mesostructures to Tungsten Nanowires". Angewandte Chemie. 114 (2): 333–335. Bibcode:2002AngCh.114..343L. doi:10.1002/1521-3773(20020118)41:2<333::AID-ANIE333>3.0.CO;2-5. PMID 12491423.
115. Volker Cimalla (2008). "Nanomechanics of single crystalline tungsten nanowires". Journal of Nanomaterials. 2008: 1–9. doi:10.1155/2008/638947. hdl:11858/00-001M-0000-0019-4CC6-3.
116. CNR Rao (2006). "High-sensitivity hydrocarbon sensors based on tungsten oxide nanowires". Journal of Materials Chemistry.
117. Liu, M.; Peng, J.; et al. (2016). "Two-dimensional modeling of the self-limiting oxidation in silicon and tungsten nanowires". Theoretical and Applied Mechanics Letters. 6 (5): 195–199. arXiv:1911.08908. Bibcode:2016TAML....6..195L. doi:10.1016/j.taml.2016.08.002.
118. JTL Thong (2010). "Thermal oxidation of polycrystalline tungsten nanowire" (PDF). Journal of Applied Physics. 108 (9): 094312–094312–6. Bibcode:2010JAP...108i4312Y. doi:10.1063/1.3504248. Archived (PDF) from the original on 2017-03-15.
119. Pitts, R. A.; Carpentier, S.; Escourbiac, F.; Hirai, T.; Komarov, V.; Lisgo, S.; Kukushkin, A. S.; Loarte, A.; Merola, M.; Sashala Naik, A.; Mitteau, R. (2013-07-01). "A full tungsten divertor for ITER: Physics issues and design status". Journal of Nuclear Materials. Proceedings of the 20th International Conference on Plasma-Surface Interactions in Controlled Fusion Devices. 438: S48–S56. Bibcode:2013JNuM..438S..48P. doi:10.1016/j.jnucmat.2013.01.008. ISSN 0022-3115.
120. Johnson JL, Rajagopalan KV, Mukund S, Adams MW. (5 March 1993). "Identification of molybdopterin as the organic component of the tungsten cofactor in four enzymes from hyperthermophilic Archaea". Journal of Biological Chemistry. 268 (7): 4848–52. doi:10.1016/S0021-9258(18)53474-8. PMID 8444863.{{cite journal}}: CS1 maint: multiple names: authors list (link)
121. Lassner, Erik (1999). Tungsten: Properties, Chemistry, Technology of the Element, Alloys and Chemical Compounds. Springer. pp. 409–411. ISBN 978-0-306-45053-2.
122. Stiefel, E. I. (1998). "Transition metal sulfur chemistry and its relevance to molybdenum and tungsten enzymes" (PDF). Pure Appl. Chem. 70 (4): 889–896. CiteSeerX 10.1.1.614.5712. doi:10.1351/pac199870040889. S2CID 98647064. Archived (PDF) from the original on 2008-12-03.
123. Khangulov, S. V.; et al. (1998). "Selenium-Containing Formate Dehydrogenase H from Escherichia coli: A Molybdopterin Enzyme That Catalyzes Formate Oxidation without Oxygen Transfer". Biochemistry. 37 (10): 3518–3528. doi:10.1021/bi972177k. PMID 9521673.
124. ten Brink, Felix (2014). "Chapter 2. Living on acetylene. A Primordial Energy Source". In Peter M.H. Kroneck; Martha E. Sosa Torres (eds.). The Metal-Driven Biogeochemistry of Gaseous Compounds in the Environment. Metal Ions in Life Sciences. Vol. 14. Springer. pp. 15–35. doi:10.1007/978-94-017-9269-1_2. ISBN 978-94-017-9268-4. PMID 25416389.
125. Schrader, Thomas; Rienhofer, Annette; Andreesen, Jan R. (1999). "Selenium-containing xanthine dehydrogenase from Eubacterium barkeri". Eur. J. Biochem. 264 (3): 862–71. doi:10.1046/j.1432-1327.1999.00678.x. PMID 10491134.
126. Andreesen, J. R.; Makdessi, K. (2008). "Tungsten, the Surprisingly Positively Acting Heavy Metal Element for Prokaryotes". Annals of the New York Academy of Sciences. 1125 (1): 215–229. Bibcode:2008NYASA1125..215A. doi:10.1196/annals.1419.003. PMID 18096847. S2CID 19459237.
127. Petkewich, Rachel A. (19 January 2009). "Unease over Tungsten". Chemical & Engineering News. 87 (3): 63–65. doi:10.1021/cen-v087n003.p063.
128. Inouye, L. S.; et al. (2006). "Tungsten effects on survival, growth, and reproduction in the earthworm, eisenia fetida". Environmental Toxicology and Chemistry. 25 (3): 763–8. doi:10.1897/04-578R.1. PMID 16566161. S2CID 38620368.
129. McQuaid A; Lamand M; Mason J (1994). "Thiotungstate-copper interactions II. The effects of tetrathiotungstate on systemic copper metabolism in normal and copper-treated rats". J Inorg Biochem. 53 (3): 205–18. doi:10.1016/0162-0134(94)80005-7. PMID 8133256.
130. Paul Blum, ed. (1 April 2008). Archaea: New Models for Prokaryotic Biology. Caister Academic Press. ISBN 978-1-904455-27-1.
131. Brown, Mark (7 September 2011). "The Earth's most precious metals arrived on meteorites". wired.co.uk.
132. Strigul, N; Koutsospyros, A; Arienti, P; Christodoulatos, C; Dermatas, D; Braida, W (2005). "Effects of tungsten on environmental systems". Chemosphere. 61 (2): 248–58. Bibcode:2005Chmsp..61..248S. doi:10.1016/j.chemosphere.2005.01.083. PMID 16168748.
133. Krebs, Robert E. (2006-07-30). The History and Use of Our Earth's Chemical Elements: A Reference Guide. Bloomsbury Publishing USA. ISBN 978-0-313-02798-7.
134. Laulicht, F.; Brocato, J.; Cartularo, L.; Vaughan, J.; Wu, F.; Vaughan, J.; Kluz, T.; Sun, H.; Oksuz, B. A.; Shen, S.; Peana, M.; Medici, S.; Zoroddu, M. A.; Costa, M. (2015). "Tungsten-induced carcinogenesis in human bronchial epithelial cells". Toxicology and Applied Pharmacology. 288 (1): 33–39. Bibcode:2015ToxAP.288...33L. doi:10.1016/j.taap.2015.07.003. PMC 4579035. PMID 26164860.
135. Zoroddu, M. A.; Medici, S.; Peana, M.; Nurchi, V. M.; Lachowicz, J. I.; Laulicht, J.; Costa, M. (2017). "Tungsten or Wolfram: Friend or Foe?". Curr. Med. Chem. 24 (1): 65–90. doi:10.2174/0929867324666170428105603. PMID 27855621.
136. 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. Bibcode:2006JHzM..136....1K. doi:10.1016/j.jhazmat.2005.11.007. PMID 16343746.
137. Lagarde, F.; Leroy, M. (2002). Metabolism and toxicity of tungsten in humans and animals. Metal Ions in Biological Systems. Vol. 39. pp. 741–59. doi:10.1201/9780203909331.ch22. ISBN 978-0-8247-0765-1. PMID 11913143. also reported in Astrid Sigel; Helmut Sigel (2002). Molybdenum and tungsten: their roles in biological processes. CRC Press. p. 741 ff. ISBN 978-0-8247-0765-1.
138. 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.
139. 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. doi:10.1520/JFS14162J. PMID 9144946.
140. "CDC – NIOSH Pocket Guide to Chemical Hazards – Tungsten". www.cdc.gov. Archived from the original on 2015-11-25. Retrieved 2015-11-24.
141. "Google Trends". Google Trends. Archived from the original on 2023-12-08. 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