Tungsten, a metallic element. Atomic number 74, atomic weight 183.84. Steel gray or silver white, high hardness, high melting point, free from air erosion under normal temperature; mainly used for manufacturing filament and high-speed cutting alloy steel, superhard mold, also used for optical instruments, chemical instruments. China is the largest tungsten storage country in the world.
Tungsten is a metal element. The chemical element symbol of tungsten is w, the atomic number is 74, the relative atomic mass is 183.85, the atomic radius is 137 PI meters, and the density is 19.35g/cm3. It belongs to the VIB family of the sixth period (the second long period) in the periodic table of elements. Tungsten is mainly hexavalent cation in nature, and its ion radius is 0.68 × 10-10m. Due to the small radius of W6 + ions, high electricity price, strong polarization ability, and easy to form complex anions, tungsten is mainly in the form of complex anions [WO4] 2 -, combined with Fe2 +, Mn2 +, Ca2 + and other cations in the solution to form wolframite or scheelite precipitation. After smelting, tungsten is silvery white lustrous metal with high melting point, high hardness, low vapor pressure, low evaporation rate and stable chemical properties.