Se Selenium     Atomic number : 34 
    Relative atomic mass (12C = 12.0000) :  78.96 
    P H Y S I C A L     D A T A
Group 16 non-metal
 
Density / kg m-3 :  4790 (grey) [293 K]; 3987 [liquid at m.p.]
 
Melting point / K :  490 
 
Boiling point / K :  958.1
 
    D I S C O V E R Y
Discovered in 1817 by J.J. Berzelius at Stockholm, Sweden.
 
    G E O L O G I C A L     D A T A
Abundances
 
Sun (relative to H = 1 × 1012) : n.a.
 
Earth's crust / p.p.m. : 0.05
 
Residence time / years : 3000
 
Classification : recycled
 
Oxidation state : VI (mainly) and IV
 
  
 
Seawater / p.p.m. :
    Atlantic surface : 0.46 × 10-7
    Atlantic deep : 1.8 × 10-7
    Pacific surface : 0.15 × 10-7
    Pacific deep : 1.65 × 10-7
    B I O L O G I C A L     D A T A
Level in humans
 
Blood / mg dm-3 : 0.171
 
Bone / p.p.m. : 1 - 9
 
Liver / p.p.m. : 0.35 - 2.4
 
Muscle / p.p.m. : 0.42 - 1.9
 
  
 
Daily dietary intake : 0.006 - 0.2 mg
 
Total mass of element
in average (70 kg) person :
c. 15 mg (wide range possible, 10 - 65 mg)

 

NetElements II  

A portrait of selenium is available on the Visual Elements site. Up to 200 individual items of information on this element are available in The Elements.


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NetElements II last modified October 27th, 1999