OSMIUM (OS)

last update 01 oct 08

* Osmium is a member of the transition metals family:

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   OSMIUM / Os / 76

   A lustrous, silvery, unreactive metal, the densest metal known.
   Seven isotopes are found in nature:

     Os<192/76> / 41%
     Os<190/76> / 26.5%
     Os<189/76> / 16%
     Os<188/76> / 13.5%
     Os<187/76> /  1.5%
     Os<186/76> /  1.5%
     Os<184/76> /  0.02%

   All are stable except for Os<186/76>, which has a half-life of 
   2E15 years.

     atomic weight:       190.23
     abundance:           81st (very rare)
     density:             22.57 g/cc
     melting point:       3,045 C
     boiling point:       5,027 C
     valence:             1 2 3 <4> 5 6 7 8
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Osmium is a member of the platinum group of metals. It is rare and hard to extract, and so it is little used despite its hardness and corrosion resistance. It is used a bit in alloys and catalytic processes.