出典:Wiktionary
rhenium (countable かつ uncountable, 複数形 rheniums)
出典:Wikipedia
出典:『Wikipedia』 (2011/07/18 20:42 UTC 版)
Rhenium (pronunciation: /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. The free element has the third-highest melting point of any element, exceeded only by tungsten and carbon. 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.