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1803 von S. Tennant in London, UK, entdeckt.
[Griechisch, osme = Geruch]
French: osmium
English: osmium
Italian: osmio
Spanish: osmio
Beschreibung: Glänzendes, silberfarbiges Metall der Platingruppe. Es wird nicht von Luft, Wasser und Säuren angegriffen, löst sich aber in geschmolzenen Alkalien. Wegen der Bildung von flüchtigen OsO4 stark riechend. Verwendung in Legierungen und für Katalysatoren.
Crystal structure: |
(cell dimensions/pm), space group, |
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X-ray diffractions mass absorption coefficients: | CuKa 186 (µ/r) / cm2g-1 MoKa 106 (µ/r) / cm2g-1 |
Neutron scattering length: | 1.07 b/10-12 cm |
Thermal neutron capture cross-section: | 15 sa / barns |
Density: | 22 590 kg/m-3 [293 K] |
Melting point: | 3053.85°C / 3327°K |
Boiling point: | 5026.85°C / 5300°K |
Molar volume: | 8.43 cm3 |
Thermal conductivity: | 87.6 [300 K] W m-1K-1 |
Coefficient of linear thermal expansion: | 4.3 x 10-6 (a axis); 6.1 x 10-6 (b axis); 6.8 x 10-6 (c axis) K-1 |
Electrical resistivity: | 8.12 x 10-8 [273 K] Ωm |
Mass magnetic susceptibility: | +6.5 x 10-10(s) kg-1m3 |
Radi: | Os4+ 67; Os3+ 81; Os2+ 89; atomic 135; covalent 126 |
Electronegativity: | 2.2 (Pauling); 1.52 (Allred); 4.9 eV (absolute) |
Effective nuclear charge: | 3.75 (Slater); 10.32 (Clementi); 14.90 (Froese-Fischer) |
Number of Isotopes (incl. nuclear isomers): | 37 |
Isotope mass range: | 166 -> 196 |
Biological role: | None. |
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Toxicity | The metal itself is not toxic but its volatile oxide, OsO4, is. |
Toxic intake: | oxide, inhalation, human = 133 µg m-3 |
Lethal intake: | LD50 (oxide, oral, rat) = 162 mg kg-1 |
Hazards: | Osmium dust is an irritant to eyes, skin and mucous membranes. |
Level in humans | n.a. but very low |
Daily dietary intake: | n.a. |
Total mass of element in average [70 kg] person: |
n.a. but very low |
Minerals: | Found in free state and as alloy with iridium. | |||
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Mineral | Formula | Density | Hardness | Crystal apperance |
Osmiridium | (Ir,Os) | c. 20 | 6 - 7 | cub. met. white |
Osmium | Os | 22.48 | 7 | hex. met. white |
Chief ores: | obtained as a by-product of nickel refining |
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World production: | 0.06 tonnes/year |
Producing areas: | see nickel |
Reserves: | n.a. |
Specimen: | available as powder or sponge. Danger! |
Abundances | |
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Sun: | 5 (relative to H = 1 x 1012) |
Earth's crust: | c. 1 x 10-4 ppm |
Seawater | n.a. but minute |
Source: Emsley, J. (1998) The Elements (3rd Edition)
Other sizes and specifications on request