Tungsten

Tungsten - W

CAS: 7440-33-7
Description: Hard, silver-white metal
Classification: Transition Metal
Date of Discovery: 1783
Discoverer: Fausto and Juan Jose de Elhuyar
Name Origin: Swedish tung sten, "heavy stone"
Symbol Origin: German wolfram

Atomic Number: 74
Number of Neutrons: 110
Atomic Mass: 183.84(1) amu
Melting Point: 3422 ± 20 °C
Boiling Point: 5555 °C
Density (293 K): 19.3 g/cm³
Atomic volume: 9.53 cm³/mol
Electrical resistivity: 0.189 10^-6/cm

Thermal conductivity: 1.74 W/cmK
Enthalpy of atomization: 837 kJ/mol (est.)
Enthalpy of vaporization: 824.0 kJ/mol
Enthalpy of fusion: 35.40 kJ/mol
Specific heat capacity: 0.13 J/gK

Energy levels: 2-8-18-32-12-2
Electron configuration: [Xe]4f ¹⁴5d⁴6s²
Crystal Structure: Cubic
Atomic radius: 2.02 Å
Covalent radius: 1.30 Å
Oxidation States: +2, +3, +4, +5, or +6
Electronegativity, Pauling: 2.36
Electron affinity: 0.815 eV
First ionization energy: 7.98 eV
2nd ionization energy:
3rd ionization energy:
Polarizability: 11.1 10^-24cm³

Isotope	Natural Abundance	Atomic Mass	Half-life	Decay Mode	Spin
^158mW	< 1 ms
¹⁵⁸W	157.974	0.9 s
¹⁵⁹W	158.972	7 ms
¹⁶⁰W	159.9684	0.08 s		0+
¹⁶¹W	160.9671	⁺, EC;
¹⁶²W	161.9626	1.39 s	⁺, EC;	0+
¹⁶³W	162.9624	2.8 s	⁺, EC;
¹⁶⁴W	163.95890	6 s	⁺, EC;	0+
¹⁶⁵W	164.9583	5.1 s	⁺, EC;
¹⁶⁶W	165.95502	16 s	⁺, EC;	0+
¹⁶⁷W	166.9547	20 s	EC
¹⁶⁸W	167.9519	53 s	EC;
¹⁶⁹W	168.9518	1.3 m	EC
¹⁷⁰W	169.9485	2.4 m	EC
¹⁷¹W	170.9494	2.4 m	EC
¹⁷²W	171.9474	6.6 m	⁺, EC
¹⁷³W	172.9489	6.3 m	EC
¹⁷⁴W	173.9462	35 m	EC	0+
¹⁷⁵W	174.9468	35 m	EC	1/2-
¹⁷⁶W	175.9456	2.5 h	⁺, EC	0+
¹⁷⁷W	176.9466	2.21 h	EC	(1/2-)
¹⁷⁸W	177.9459	21.6 d	EC	0+
^179mW	6.4 m	IT; EC	(1/2-)
¹⁷⁹W	178.94707	38 m	EC	(7/2-)
¹⁸⁰W	0.120(1)	179.946706	Stable	0+
¹⁸¹W	180.94820	121.2 d	EC	9/2+
¹⁸²W	26.498(29)	181.948205	Stable	0+
^183mW	5.15 s	IT	(11/2+)
¹⁸³W	14.314(4)	182.950224	Stable	1/2-
¹⁸⁴W	30.642(8)	183.950932	Stable	0+
^185mW	1.6 m	IT	11/2+
¹⁸⁵W	184.953420	74.8 d	^-	3/2-
¹⁸⁶W	28.426(37)	185.954362	Stable	0+
¹⁸⁷W	186.957158	23.9 h	^-	3/2-
¹⁸⁸W	187.958487	69.4 d	^-	0+
¹⁸⁹W	188.9619	11.5 m	^-	(3/2-)
¹⁹⁰W	189.9632	30 m	^-	0+
Also known as wolfram (from wolframite, said to be named from wolf rahm or spumi lupi, because the ore interfered with the smelting of tin and was supposed to devour the tin). In 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)WO₂; scheelite, CaWO₄; huebnerite, MnWO₄; and ferberite, FeWO₄. Important deposits of tungsten occur in California, Colorado, South Korea, 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 fumaces; 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. LINKS: International Tungsten Industry Association Material Safety Data Sheet - Tungsten Properties of Tungsten Scientific American: Working Knowledge: Halogen Lights Tungsten and Molybdenum Materials Return Sources for the information on this website include: Lide, David R., ed. CRC Handbook of Chemistry and Physics, 78th Ed., 1997-1998.

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