International Tungsten
Industry Association

Home > About Tungsten > Properties

Properties

Tungsten and Wolfram are the names given to element 74 of Mendeleev's Periodic Chart of the Elements. Its chemical symbol is W. 

Tungsten is a metal of many superlatives. It has not only the highest melting point of all elements except carbon (3422^°C) but also excellent high temperature mechanical properties and the lowest expansion coefficient of all metals. A temperature of about 5,700°C is needed to bring tungsten to boil - which corresponds approximately to the temperature of the sun’s surface. With its density of 19.25 g/cm³, tungsten is also among the heaviest metals. Its electrical conductivity at 0^°C is about 28% of that of silver which itself has the highest conductivity of all metals.

Tungsten features the lowest vapour pressure of all metals, very high moduli of compression and elasticity, very high thermal creep resistance and high thermal and electrical conductivity. Tungsten is the most important metal for thermoemission applications, not only because of its high electron emissivity (which is caused by additions of foreign elements) but because of its high thermal and chemical stability.
 

Electron beam molten
piece of tungsten metal

Tungsten is a shiny white metal and, in its purest form, is quite pliant and can easily be processed. Usually, however, it contains small concentrations of carbon and oxygen, which give tungsten metal its considerable hardness and brittleness. For decades, scientists have worked to overcome the brittleness problem.

Most of these unusual properties are due to the half-filled 5d electron shells (d⁵s¹) with a very high binding energy of the tungsten in the bcc tungsten crystal arising from the strong, unsaturated covalent bonds. Based on these properties, tungsten, tungsten alloys and some tungsten compounds cannot be substituted in many important applications in different fields of modern technology.