A metallic chemical element; symbol Re. Atomic number 75; atomic weight 186.207; melting point about 3,180°C; boiling point about 5,625°C. Rhenium is a very dense, high-melting, silver-white metal; specific gravity 21.02 at 20°C. Of the elements, only carbon and tungsten have higher melting points and only iridium, osmium, and platinum are more dense. It was discovered by x-ray spectroscopy in 1925 by the German chemists, Walter Noddack, Ida Tacke and Otto Berg.
The name derives from L. rhenus for "the Rhine river in Germany".