n.
or wolfram
Metallic chemical element , one of the transition element s, chemical symbol W, atomic number 74.
Exceptionally strong, white to grayish, and brittle, it has the highest melting point (6,170 °F [3,410 °C]), greatest high-temperature strength, and lowest thermal expansion coefficient of any metal . Its chief uses are in steel s to increase hardness and strength and in lightbulb filaments (see incandescent lamp ). It is also used in electrical contacts, rocket nozzles, chemical apparatus, high-speed rotors, and solar-energy devices. Tungsten is relatively inert, but compounds (in which it has various valence s) are known. The most important, tungsten carbide , noted for its hardness, is used to increase the wear-resistance of cast iron and of tools' cutting edges.