| Se | Selenium | Atomic number : 34 Relative atomic mass (12C = 12.0000) : 78.96 |
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| 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. |
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| 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) |
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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. |