Tungsten or Wolfram Facts

Chemical & Physical Properties of Tungsten

These are high-purity tungsten or wolfram rods, crystals and a cube.
These are high-purity tungsten or wolfram rods, crystals and a cube. The crystals on the tungsten rod show a colorful oxidation layer. Alchemist-hp

Tungsten is a grayish-white transition metal with atomic number 74 and element symbol W. The symbol comes from another name for the element—wolfram. While the name tungsten is approved by the IUPAC and is used in Nordic countries and those speaking English or French, most European countries use the name wolfram. Here is a collection of tungsten or wolfram facts, including the element's properties, uses, and sources.

Tungsten or Wolfram Basic Facts

Tungsten Atomic Number: 74

Tungsten Symbol: W

Tungsten Atomic Weight: 183.85

Tungsten Discovery: Juan Jose and Fausto d'Elhuyar purified tungsten in 1783 (Spain), although Peter Woulfe examined the mineral which came to be known as wolframite and determined that it contained a new substance.

Tungsten Electron Configuration: [Xe] 6s2 4f14 5d4

Word Origin: Swedish tung sten, heavy stone or wolf rahm and spumi lupi, because the ore wolframite interfered with tin smelting and was believed to devour the tin.

Tungsten Isotopes: Natural tungsten consist of five stable isotopes. Twelve unstable isotopes are known.

Tungsten Properties: Tungsten has a melting point of 3410+/-20°C, boiling point of 5660°C, specific gravity of 19.3 (20°C), with a valence of 2, 3, 4, 5, or 6. Tungsten is a steel-gray to tin-white metal. Impure tungsten metal is quite brittle, although pure tungsten can be cut with a saw, spun, drawn, forged, and extruded. Tungsten has the highest melting point and the lowest vapor pressure of the metals. At temperatures exceeding 1650°C, it has the highest tensile strength. Tungsten oxidizes in air at elevated temperatures, although it generally has excellent corrosion resistance and is minimally attacked by most acids.

Tungsten Uses: The thermal expansion of tungsten is similar to that of borosilicate glass, so the metal is used for glass/metal seals. Tungsten and its alloys are used to make filaments for electric lamps and television tubes, as electrical contacts, x-ray targets, heating elements, for metal evaporation components, and for numerous other high temperature applications. Hastelloy, Stellite, high-speed tool steel, and numerous other alloys contain tungsten. Magnesium and calcium tungstenates are used in fluorescent lighting. Tungsten carbide is important in the mining, metalworking, and petroleum industries. Tungsten disulfide is used as a dry high-temperature lubricant. Tungsten bronze and other tungsten compounds are used in paints.

Tungsten Sources: Tungsten occurs in wolframite, (Fe, Mn)WO4, scheelite, CaWO4, ferberite, FeWO4, and huebnerite, MnWO4. Tungsten is produced commercially by reducing tungsten oxide with carbon or hydrogen.

Biological Role: Tungsten is the heaviest element with known biological functionality. No use in humans or other eukaryotes is known, but the element is used by bacteria and archaea in enzymes, principally as a catalyst. It functions in much the same ways as the element molybdenum does in other organisms. When tungsten compounds are introduced to soil, they inhibit earthworm reproduction. Scientists are studying the use of tetrathiotungstates for use in biological copper chelation. Tungsten is a rare element, initially thought to be inert and only slightly toxic to humans. However, now it is known tungsten dust inhalation, skin contact, or ingestion can cause cancer and other negative health effects.

Tungsten or Wolfram Physical Data

Element Classification: Transition Metal

Density (g/cc): 19.3

Melting Point (K): 3680

Boiling Point (K): 5930

Appearance: tough gray to white metal

Atomic Radius (pm): 141

Atomic Volume (cc/mol): 9.53

Covalent Radius (pm): 130

Ionic Radius: 62 (+6e) 70 (+4e)

Specific Heat (@20°C J/g mol): 0.133

Fusion Heat (kJ/mol): (35)

Evaporation Heat (kJ/mol): 824

Debye Temperature (K): 310.00

Pauling Negativity Number: 1.7

First Ionizing Energy (kJ/mol): 769.7

Oxidation States: 6, 5, 4, 3, 2, 0

Lattice Structure: Body-Centered Cubic

Lattice Constant (Å): 3.160

Sources

  • Lide, David R., ed. (2009). CRC Handbook of Chemistry and Physics (90th ed.). Boca Raton, Florida: CRC Press. ISBN 978-1-4200-9084-0.
  • Hille, Russ (2002). "Molybdenum and tungsten in biology". Trends in Biochemical Sciences. 27 (7): 360–367. doi:10.1016/S0968-0004(02)02107-2
  • Lassner, Erik; Schubert, Wolf-Dieter (1999). Tungsten: properties, chemistry, technology of the element, alloys, and chemical compounds. Springer. ISBN 978-0-306-45053-2.
  • Stwertka, Albert (2002). A Guide to the Elements (2nd ed.). New York: Oxford University Press. ISBN 978-0-19-515026-1.
  • Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. ISBN 0-8493-0464-4.