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 or Wolfram Basic Facts

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.

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

References: Los Alamos National Laboratory (2001), Crescent Chemical Company (2001), Lange's Handbook of Chemistry (1952), CRC Handbook of Chemistry & Physics (18th Ed.)


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