Вольфрам

 

Atomic number       74

Atomic mass         183.85

Density, kg / m?       19300

Temperature

melting, ° С           3410

 

Tungsten is a hard shiny silver-gray transition metal. In 1781, the famous Swedish chemist Scheele, treating the scheelite mineral with nitric acid, obtained a yellow “heavy stone” (tungsten trioxide). In 1783, the Spanish chemists Eluard brothers reported on obtaining from the Saxon mineral wolframite both a yellow oxide of a new metal soluble in ammonia, and the metal itself. The refractoriness and plasticity of tungsten make it indispensable for filaments in lighting fixtures, as well as in picture tubes and other vacuum tubes.