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Osmium 60Os190.2
Discovered in 1803 by S. Tennant at London, England.
[Greek: osme = smell]
French: osmium
German: Osmium
Italian: osmio
Spanish: osmio
Description: Osmium is a
lustrous, silvery metal of the so-called platinum group. It is unaffected by
air, water, and acids, but dissolves in molten alkalis. Osmium metal gives off a
recognizable smell due to the formation of volatile osmium tetroxide, OsO4 . the metal is used in alloys and catalysts.
Materials properties
| Density: |
22 590 kg/m-3 [293 K]; 20 100 [liquid at m.p.] |
| Melting point: |
3327 °K |
| Boiling point: |
5300 °K |
| Molar volume: |
8.43 cm3 |
| Thermal conductivity: |
87.6 [300 K] Wm-1K-1 |
| Coefficient of linear thermal expansion: |
4.3 x 10-6 K-1 (a axis); 6.1 x 10-6 K-1 (b axis); 6.8 x 10-6 K-1 (c axis) |
| Electrical resistivity: |
8.12 x 10-8 [273 K] Wm |
| Mass magnetic susceptibility: |
+6.5 x 10-10(s) kg-1m3 |
| Young's modulus: |
559 GPa |
| Rigidity modulus: |
223 GPa |
| Bulk modulus: |
373 GPa |
| Poisson's ratio: |
0.25 GPa |
| Radii: |
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 |
| Issotope mass range: |
166 -> 196 |
Biological data
| Biological role: |
None. |
| 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 |
|
| Organs: |
n.a. but low |
| Daily dietary intake : |
n.a. |
| Total mass of element in average [70 kg] person: |
n.a. but very low |
Crystal data
| Crystal structure, (cell dimentions / pm), space group |
h.c.p. (a=273.43, c=432.00) P63/mmc |
| X-ray diffraction: mass absorption coefficients (µ/ρ) /cm2g-1 : |
CuKα 186 MoKα 106 |
| Neutron scattering length, b/10-12cm: |
1.07 |
| Thermal neutron capture cross-section, σa/barns: |
15 |
Geological data
| Minerals: |
Found in free state and as alloy with iridium. |
| 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 ore: |
obtained as a by-product of nickel refining |
| World production: |
0.06 tonnes/year |
| Main mining areas: |
see nickel |
| Reserves: |
n.a. |
| Specimen: |
available as powder or sponge. Danger! |
| Abundances |
|
| Sun: |
5 (relative to H = 1 x 1023) |
| Earth's crust: |
1 x 10-4 p.p.m. |
| Seawater: |
n.a. but minute |
Other sizes and specifications on request
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