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Atomic symbol: Os |
Atomic number: 76 |
Atomic weight: 190.2 |
Atomic volume: 8.49 cm3/mol |
Density: 22.40 g/cm3 |
Period Number: 6 |
Group number: 8 |
Group name: Trans. Met. |
Element classification: Metal |
Phase at room temperature: Solid |
Melting Point: 3318.2 K |
Boiling point: 5298 K |
Heat of fusion: 31.80 kJ/mol |
Heat of vaporization: 746.0 kJ/mol |
Ionization Energy: 8.7 eV |
1st ionization energy: 840 kJ/mole |
2nd ionization energy: kJ/mole |
3rd ionization energy: kJ/mole |
Electronegativity: 2.2 |
Electron affinity: 110 kJ/mole |
Specific heat: 0.13 J/gK |
Heat atomization: 791 kJ/mole atom |
Shells: 2,8,18,32,14,2 |
Electron Shell Configuration: [Xe] 4f14 5d6 6s2 |
Minimum oxidation number: -2 |
Maximum oxidation number: 8 |
Minimum common oxidation number: 0 |
Maximum common oxidation no: 4 |
Appearance & Characteristics |
Structure:: hcp: hexagonal close pkd |
Color: bluish-white |
Hardness: 7 mohs |
Toxicity: ? |
Characteristics: hard, dense, inert <1000 C |
Uses: hard alloys,phono needles |
Reaction with air: none |
Reaction with 6M HCl: none |
Reaction with 15M HNO3: mild, =>OsO4 |
Reaction with 6M NaOH: ? |
Number of isotopes: 7 |
Oxide(s): OsO2 OsO4 |
Hydride(s): none |
Chloride(s): OsCl3 OsCl4 OsCl5 |
Atomic Radius: 135 pm |
Ionic radius (1- ion): pm |
Ionic radius (1+ ion): pm |
Ionic radius (2- ion): pm |
Ionic radius (2+ ion): pm |
Ionic radius (3+ ion): pm |
Thermal conductivity: 87.6 J/m-sec-deg |
Electrical conductivity: 105.263 1/mohm-cm |
Polarizability: 8.5 A^3 |
Source: nickel ores (sulfides) |
Relative abundance solar system: -0.171 log |
Abundance earth's crust: -2.8 log |
Estimated crustal abundance: 1.5×10-3 milligrams per kilogram |
Estimated oceanic abundance: No Data Available |
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(Gr. osme, a smell) Discovered in 1803 by Tennant in the residue left when crude platinum is dissolved by aqua regia. |
Osmium occurs in iridosule and in platinum-bearing river sands in the Urals, North America, and South America. It is also found in the nickel-bearing ores of Sudbury, Ontario region along with other platinum metals. While the quantity of platinum metals in these ores is very small, the large tonnages of processed nickel ores make commercial recovery possible. |
The metal is lustrous, bluish white, extremely hard, and brittle even at high temperatures. It has the highest melting point and the lowest vapor pressure of the platinum group. The metal is very difficult to fabricate, but the powdered or spongy metal slowly gives off osmium tetroxide, which as a powerful oxidizing agent and has a strong smell. The tetroxide is highly toxic, and boils at 1300C.
The measured densities of iridium and osmium seem to indicate that osmium is slightly more dense than iridium, so osmium has generally been credited with being the heavier element. Calculations of the density from the space lattice which may be more reliable for these elements than actual measurements, however, give a density of 22.65 for iridium compared to 22.661 for osmium. Despite this information, no decision has been made as to which is heavier.
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The tetroxide has been used to detect fingerprints and to stain fatty tissue for microscope slides. The metal is almost entirely used to produce very hard alloys with other metals of the platinum group for fountain pen tips, instrument pivots, phonograph needles, and electrical contacts. |
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SEKOM Handelsges.m.b.H.... |
Our company is a private firm founded in 1990 with aim to develop export and import with Russia. We do promote EU industrial and consumer goods in Russia and strongly support marketing of Russian and CIS industrial products and services.
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