Rhenium

Rhenium, chemical element, symbol Re; for physical constants see Periodic Table. Rhenium was discovered by Walter Noddack, Ida Tacke, and Otto Berg in 1925. It occurs in the minerals columbite, wolframite, gadolinite, and molybdenite. It is prepared by the high-temperature reduction of ammonium with hydrogen. Rhenium is a silver-white, ductile, high-melting, dense metal. It is resistant to wear and electrical corrosion. Rhenium and its compounds are used in alloys for electrical contacts and filaments, electron tube and semiconductor applications, high-temperature thermocouples, and poison-resistant catalysts. Dmitri Mendeleev predicted this element, which he called dwi-manganese.