Rhenium

Rhenium (pronounced /ˈriːniəm/, REE-nee-əm) is a chemical element with the symbol Re and atomic number 75. It is a silvery-white, heavy, third-row transition metal in group 7 of the periodic table. With an average concentration of 1 part per billion (ppb), rhenium is one of the rarest elements in the Earth's crust. Rhenium resembles manganese chemically and is obtained as a by-product of molybdenum and copper refinement. Rhenium shows in its comp... more

Rhenium (pronounced /ˈriːniəm/, REE-nee-əm) is a chemical element with the symbol Re and atomic number 75. It is a silvery-white, heavy, third-row transition metal in group 7 of the periodic table. With an average concentration of 1 part per billion (ppb), rhenium is one of the rarest elements in the Earth's crust. Rhenium resembles manganese chemically and is obtained as a by-product of molybdenum and copper refinement. Rhenium shows in its compounds a wide variety of oxidation states ranging from −1 to +7. Minute amounts of rhenium are added into tungsten alloys and some rhenium compounds are used as catalysts in the chemical industry. Nickel-based superalloys for the use in jet engines contain up to 6% of rhenium, making it the largest use for rhenium. Because of the low availability and the demand for jet engines, rhenium is among the most expensive metals on Earth, whose price at times exceeds US$12,000 per kilogram. Rhenium, discovered in 1925, was the last naturally occurring... less