Chemical properties of tungsten

Refractory metal tungsten&moly tungsten wire is a rare , high-temperature

hardness of the steel can be improved , the sixth period of

the periodic table are ( second long cycle) Ⅵ B family.

tungsten weights is a silvery-white metal that looks like steel.

Tungsten high melting point, low vapor pressure , evaporation

rate is also small . Tungsten is chemically stable at room

temperature when not react with air and water when not

heated, any concentration of hydrochloric acid, sulfuric

acid, nitric acid, hydrofluoric acid and aqua regia tungsten tube

are ineffective when the temperature was raised to 80 ° -100

when ° C, these various acids , except hydrofluoric acid ,

the other weak acid on the role of tungsten occur . At room

temperature , can be quickly dissolved in a mixture of

tungsten acid, hydrofluoric acid and concentrated nitric acid

, it does not work in an alkaline solution. The presence of

air under the conditions of the tungsten oxide can be melted

into the base tungstate , in the presence of an oxidant

(NaNO3, NaNO2, KClO3, PbO2) exists , the generation of a more

violent reaction tungstate . High temperature with chlorine,

bromine , iodine , carbon, nitrogen , sulfur and other

compounds , but not together with the hydrogenation .