Rhenium

Rhenium metal is a rare and sparse metallic element with a silvery-white luster that is found in the earth's crust at very low levels of 10-910^{-9}10
-9
. Rhenium powder is black in color and will gradually turn gray when heated. The atomic weight of rhenium is 186.207, the electron arrangement is [Xe] 4f14 5d5 6s2, and the electronegativity is 1.9 (Bowling scale). Rhenium has excellent hardness, wear resistance, corrosion resistance and other physicochemical properties, its density is 21.04g/cm3, melting point is 3180 ℃, boiling point up to 5627 ℃, is the highest of all metals. These characteristics of rhenium make it a very important strategic materials, aircraft, rockets and other aviation, aerospace, military and other fields have a wide range of applications.