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Tungsten

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Products Intro: Product Name:Tungsten
CAS:7440-33-7
Purity:99% Package:100g,500g,1kg,5kg,10kg
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CAS:7440-33-7
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Products Intro: Product Name:Tungsten Target /Φ50.8x6.3mm/99.95%
CAS:7440-33-7
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Products Intro: Product Name:tungsten atom
CAS:7440-33-7
Purity:0.999 Package:10g;50g;100g;500g;1kg;5kg;25kg
Tungsten Basic information
History and Occurrence Uses Physical Properties Production Reactions
Product Name:Tungsten
Synonyms:Tungsten, nanopowder, >=99.9%;Tungsten, foil, 0.05mm thick, 99.9+% metals basis;TUNGSTEN, WIRE, 0.25MM DIAM., 99.9+%;TUNGSTEN, FOIL, 0.25MM THICK, 99.9+%;TUNGSTEN FOIL 1.0MM THICK 99.9+%;TUNGSTEN, WIRE, 0.5MM DIAM., 99.9+%;TUNGSTEN, POWDER, 12 MICRON, 99.9%;TUNGSTEN, POWDER, CA. 100 MESH, 99.95%
CAS:7440-33-7
MF:W
MW:183.84
EINECS:231-143-9
Product Categories:74: W;TungstenNanomaterials;Materials Science;Nanomaterials;Nanoparticles: Metals and Metal AlloysMetal and Ceramic Science;Nanopowders and Nanoparticle Dispersions;Metal and Ceramic Science;Metals;Tungsten;metal or element;Inorganics
Mol File:7440-33-7.mol
Tungsten Structure
Tungsten Chemical Properties
Melting point 3410 °C(lit.)
Boiling point 5660 °C(lit.)
density 19.3 g/mL at 25 °C(lit.)
Fp -23 °C
form wire
color Silver-gray
resistivity4.9 μΩ-cm, 20°C
Water Solubility insoluble
Merck 13,9884
Stability:Stable. Dust is flammable, though not likely to present a hazard if normal good practice is used.
CAS DataBase Reference7440-33-7(CAS DataBase Reference)
NIST Chemistry ReferenceTungsten(7440-33-7)
EPA Substance Registry SystemTungsten(7440-33-7)
Safety Information
Hazard Codes F,Xi,N,Xn
Risk Statements 11-36/38-67-65-62-51/53-48/20-38
Safety Statements 6-26-36-62-61-36/37-16
RIDADR UN 3089 4.1/PG 2
WGK Germany -
RTECS YO7175000
TSCA Yes
HazardClass 4.1
PackingGroup III
Hazardous Substances Data7440-33-7(Hazardous Substances Data)
MSDS Information
ProviderLanguage
Tungsten English
SigmaAldrich English
ACROS English
ALFA English
Tungsten Usage And Synthesis
History and OccurrenceThe discovery of tungsten occurred in the 1780’s. Peter Woulfe, in 1779, while examining the mineral now known as wolframite, established that it contained a new substance. Around the same time, Swedish chemist Carl Wilhelm Scheele was investigating another mineral, scheelite. This mineral was known at that time as tungsen, which in Swedish meant heavy stone. Scheele, in 1781, determined that tungsen contained lime and a new acid similar to molybdic acid. This new acid was tungstic acid. Scheele and Bergman predicted that reduction of this acid could produce a new metal. Two years later in 1783, J. J. de Elhuyar and his brother F. deElhuyar of Spain first prepared metallic tungsten from wolframite. They derived an acid from wolframite which was similar to acid obtained by Scheele from tungsten (scheelite), and succeeded in producing a new metal by reduction of this acid with charcoal. Also, they determined that the mineral wolframite contained iron and manganese. The metal took over the old name of its mineral tungsten. Also the metal is known as wolfram, derived from the name of its other mineral, wolframite. The word wolfram originated from the wolf-like nature of the mineral that it devoured tin during the tin smelting operation causing low recoveries. The element was given the symbol W for its old name wolfram.
Tungsten is widely distributed in nature, occurring in several minerals. It is found in scheelite, CaWO4; wolframite, (Fe,Mn)WO4; huebnerite, MnWO4; ferberite, FeWO4; tungstite, H2WO4; and cuprotungstite, CuWO4. Its abundance in the earth’s crust is estimated to be 1.25 mg/kg and average concentration in seawater is about 0.1 μg/L.
UsesIndustrially tungsten is a very important metal having wide applications. This is due to many outstanding physical properties. Among all the metals, tungsten has the highest melting point and the lowest vapor pressure. Also at high temperatures it has the highest tensile strength. The metal has an excellent resistance to corrosion and attack by mineral acids. Also it has a thermal expansion comparable to that of borosilicate glass.
Tungsten is extensively used in alloy steel to impart high strength and hardness to steel. Heavy metal alloys with nickel, copper and iron, produced by powder metallurgy, can be made machineable and moderately ductile for applications as high-density materials. Tungsten carbides are extremely hard and are excellent cutting materials. They are used extensivly in the tool and die industry for drilling and cutting tools, sand blasting nozzels, armor-piercing bullets, and studs to increase traction of tires.
Among the nonferrous tungsten alloys, its alloys with copper and silver are used as electrical contacts and switches and with molybdenum in aerospace components.
Unalloyed tungsten has several major applications. An important use is in the electric lamp filaments for light bulbs. Also, it is used as electrodes in arcwelding, in heating elements for high-temperature furnaces, in electron and television tubes, in glass-tometal seals, and in solar energy devices.
Physical PropertiesGrayish-white metal; body-centered cubic crystalline structure; density 19.3 g/cm3; melts at 3,422°C; vaporizes at 5,555°C; vapor pressure 1 torr at 3,990°C; electrical resistivity 5.5 microhm-cm at 20°C; modulus of elasticity about 50 to 57 × 106 psi (single crystal); Poisson’s ratio 0.17; magnetic susceptibilty +59 × 10–6; thermal neutron absorption cross section 19.2 + 1.0 barns (2,200m/sec); velocity of sound, about 13,000 ft/sec; insoluble in water; practically insoluble in most acids and alkalies; dissolves slowly in hot concentrated nitric acid; dissolves in saturated aqueous solution of sodium chlorate and basic solution of potassium ferricyanide; also solubilized by fusion with sodium hydroxide or sodium carbonate in the presence of potassium nitrate followed by treatment with water.
ProductionTungsten is recovered mostly from mineral scheelite and wolframite. The recovery process depends on the mineral, the cost, and the end use; i.e., the commercial products to be made. Typical industrial processes have been developed to convert tungsten ores to tungsten metal and alloy products, tungsten steel, non-ferrous alloys, cast and cemented tungsten carbides, and tungsten compounds. A few processes are mentioned briefly below.
The first step in recovery is opening the ore. If the ore is scheelite, CaWO4, it is digested with hydrochloric acid:
CaWO4 + 2HCl → H2WO4 + CaCl2
Tungstic acid, H2WO4 precipitates out. The precipitate is washed and dissolved in sodium or ammonium hydroxide solution during heating:
H2WO4 + 2NaOH → Na2WO4 + 2H2O
Sodium tungstate is crystallized, separated from any impurities in the solution, and digested again with hydrochloric acid to form tungstic acid in purified form. The pure acid is dried, ignited and reduced with carbon to form tungsten powder from which most non-ferrous alloys are made.
ReactionsTungsten exhibits several oxidation states, +6 being most stable. Compounds of lower oxidation states show alkaline properties. They also are less stable than those produced in higher oxidation states. Tungsten exhibits remarkable stability to practically all substances at ambient temperature. The metal is not attacked by nonoxidizing mineral acid. Concentrated hydrochloric acid, dilute sulfric acid and hydrofluoric acid attack the metal very slightly even when heated to 100°C. Tungsten is stable to dilute or concentrated nitric acid under cold conditions. Cold acid passivates the surface forming a slight oxide film. Hot dilute nitric acid corrodes the metal, while hot concentrated acid slowly dissolves bulk metal but rapidly oxidizes metal in powder form. At room temperature, aqua regia oxidizes metal only on the surface forming tungsten trioxide. A hydrofluoric-nitric acid mixture rapidly oxidizes tungsten to its trioxide. Chromic acid-sulfuric acid mixture does not react with tungsten metal in ductile form at ambient temperatures.
Chemical Propertiesgrey metal chunks or grey powder
Chemical PropertiesTungsten is a hard, brittle, steel-gray to tinwhite metal or fine powder.
HistoryIn 1779 Peter Woulfe examined the mineral now known as wolframite and concluded it must contain a new substance. Scheele, in 1781, found that a new acid could be made from tung sten (a name first applied about 1758 to a mineral now known as scheelite). Scheele and Berman suggested the possibility of obtaining a new metal by reducing this acid. The de Elhuyar brothers found an acid in wolframite in 1783 that was identical to the acid of tungsten (tungstic acid) of Scheele, and in that year they succeeded in obtaining the element by reduction of this acid with charcoal. Tungsten occurs in wolframite, (Fe, Mn)WO4; scheelite, CaWO4; huebnerite, MnWO4; and ferberite, FeWO4. Important deposits of tungsten occur in California, Colorado, Bolivia, Russia, and Portugal. China is reported to have about 75% of the world’s tungsten resources. Natural tungsten contains five stable isotopes. Thirty-two other unstable isotopes and isomers are recognized. The metal is obtained commercially by reducing tungsten oxide with hydrogen or carbon. Pure tungsten is a steel-gray to tin-white metal. Very pure tungsten can be cut with a hacksaw, and can be forged, spun, drawn, and extruded. The impure metal is brittle and can be worked only with difficulty. Tungsten has the highest melting point of all metals, and at temperatures over 1650°C has the highest tensile strength. The metal oxidizes in air and must be protected at elevated temperatures. It has excellent corrosion resistance and is attacked only slightly by most mineral acids. The thermal expansion is about the same as borosilicate glass, which makes the metal useful for glass-to-metal seals. Tungsten and its alloys are used extensively for filaments for electric lamps, electron and television tubes, and for metal evaporation work; for electrical contact points for automobile distributors; X-ray targets; windings and heating elements for electrical furnaces; and for numerous spacecraft and high-temperature applications. High-speed tool steels, Hastelloy?, Stellite?, and many other alloys contain tungsten. Tungsten carbide is of great importance to the metal-working, mining, and petroleum industries. Calcium and magnesium tungstates are widely used in fluorescent lighting; other salts of tungsten are used in the chemical and tanning industries. Tungsten disulfide is a dry, high-temperature lubricant, stable to 500°C. Tungsten bronzes and other tungsten compounds are used in paints. Zirconium tungstate has found recent applications (see under Zirconium). Tungsten powder (99.999%) costs about $2900/kg.
UsesTo increase hardness, toughness, elasticity, and tensile strength of steel; manufacture of alloys; manufacture of filaments for incandescent lamps and in electron tubes; in contact points for automotive, telegraph, radio and television apparatus; in phonograph needles. Tungsten carbides (W2C, WC) used in rock drills, metal-cutting tools, wire-drawing dies. WC used as catalyst instead of platinum: Bennett et al., Science 184, 563 (1974).
Reactivity ProfileTungsten is stable at room temperature. Very slowly attacked by nitric acid, sulfuric acid, and aqua regia. Dissolved by a mixture of hydrofluoric acid and nitric acid. No reaction with aqueous bases. Attacked rapidly by motlen alkaline melts such as Na2O2 or KNO3/NaOH. Vigorous reactions with bromine trifluoride and chlorine trifluoride. Becomes incandescent upon heating with lead oxide; becomes incandescent in cold fluorine and with iodine pentafluoride. Combustible in the form of finely divided powder and may ignite spontaneously.
Safety ProfileAn inhalation hazard. Mildly toxic by an unspecified route. An experimental teratogen. Experimental reproductive effects. A skin and eye irritant. Flammable in the form of dust when exposed to flame. The powdered metal may ignite on contact with air or oxidants (e.g., bromine pentafluoride, bromine, chlorine trifluoride, potassium perchlorate, potassium dichromate, nitryl fluoride, fluorine, oxygen difluoride, iodine pentafluoride, hydrogen sulfide, sodlum peroxide, lead (IV)oxide). See also TUNGSTEN COMPOUNDS and POWDERED METALS.
Potential ExposureTungsten is used in ferrous and nonferrous alloys, and for filaments in incandescent lamps. It has been stated that the principal health hazards from tungsten and its compounds arise from inhalation of aerosols during mining and milling operations. The principal compounds of tungsten to which workers are exposed are ammonium paratungstate, oxides of tungsten (WO3, W2O5, WO2); metallic tungsten; and tungsten carbide. In the production and use of tungsten carbide tools for machining, exposure to the cobalt used as a binder or cementing substance may be the most important hazard to the health of the employees. Since the cemented tungsten carbide industry uses such other metals as tantalum, titanium, niobium, nickel, chromium, and vanadium in the manufacturing process, the occupational exposures are generally to mixed dust.
First aidIf this chemical gets into the eyes, remove any contact lenses at once and irrigate immediately for at least 15 minutes, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts the skin, remove contaminated clothing and wash immediately with soap and water. Seek medical attention immediately. If this chemical has been inhaled, remove from exposure, begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR if heart action has stopped. Transfer promptly to a medical facility. When this chemical has been swallowed, get medical attention. Give large quantities of water and induce vomiting. Do not make an unconscious person vomit.
ShippingUN3089 Metal powders, flammable, n.o.s., Hazard Class: 4.1; Labels: 4.1-Flammable solid. UN3189 Metal powder, self heating, n.o.s., Hazard Class: 4.2; Labels: 4.2-Spontaneously combustible material.
Purification MethodsClean the solid with conc NaOH solution, rub it with very fine emery paper until its surface is bright, wash it with previously boiled and cooled conductivity water and dry it with filter paper. [Hein & Herzog in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol II p 1417 1965.]
IncompatibilitiesTungsten: The finely divided powder is combustible and may ignite spontaneously in air. Incompatible with bromine trifluoride; chlorine trifluoride; fluorine, iodine pentafluoride.
Waste DisposalRecovery of tungsten from sintered metal carbides, scrap and spent catalysts has been described as an alternative to disposal.
Tungsten Preparation Products And Raw materials
Raw materialsAmmonium paratungstate-->Tungsten trioxide
Preparation ProductsPigment Violet 3-->TUNGSTEN CARBIDE-->Fast Pure Blue lake
Tag:Tungsten(7440-33-7) Related Product Information
TUNGSTEN TELLURIDE TUNGSTEN(VI) OXYCHLORIDE Tungsten chloride (WCl6), (OC-6-11)-,Tungsten chloride, alpha,Tungsten chloride, (oc-6-11)-,TUNGSTEN(VI) CHLORIDE TUNGSTEN VI PHENOXIDE Phosphotungstic acid hydrate Tungsten, tricarbonyl(1,3,5-cycloheptatriene)-,Tungsten, tricarbonyl[(1,2,3,4,5,6-eta)-1,3,5-cycloheptatriene]-,Tricarbonyl(eta-1,3,5-cycloheptatriene)tungsten,Tricarbonyl(cycloheptatriene)tungsten Tricarbonyl(cyclopentadienyl)tungsten hydride,Tungsten, tricarbonyl-pi-cyclopentadienylhydro- TUNGSTEN TETRACHLORIDE TUNGSTEN (V) CHLORIDE Calcium tungstate TUNGSTEN TITANIUM CARBIDE TUNGSTEN STANDARD,TUNGSTEN STANDARD SOLUTION,TUNGSTEN SINGLE ELEMENT STANDARD Tungsten,hexacarbonylbis(eta-2,4-cyclopentadien-1-yl)di- [1,2-BIS(DIPHENYLPHOSPHINO)ETHANE]TUNGSTEN TETRACARBONYL Tungsten carbonyl (W(CO)6),Tungsten carbonyl (W(CO)6), (OC-6-11)- TUNGSTEN CARBIDE TungstenAlloy Sodium tungstate dihydrate