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A hard, silvery-white naturally occurring rare-earth metallic element. Rhenium was first isolated in 1925 by Noddack and Tacke using an x-ray spectrograph. It has an average concentration of 0.001 ppm in the earth's crust and is obtained from rare-earth minerals such as gadolinite, molybdenite and columbite. Rhenium is used in platinum, tungsten, and molybdenum alloys for electronic filaments and thermocouples. It is also used for plating jewelry and medical instruments as well as for backing mirrors.

Synonyms and Related Terms

Re; rhénium (Fr.); renio (It., Esp.); Rênio (Port.)

Other Properties

Reacts with oxidizing mineral acids. Insoluble in hydrochloric and hydrofluoric acids

Composition Re (atomic no. 75)
CAS 7440-15-5
Mohs Hardness 7.0
Melting Point 3180
Density 21.02
Molecular Weight atomic wt = 186.207
Boiling Point 5630

Hazards and Safety

Powder is flammable

Fisher Scientific: MSDS

Additional Information

Web Elements: Website

Sources Checked for Data in Record

  • G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 668
  • Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
  • Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997
  • The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 8343
  • The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998