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Osmium  SEE PERIODIC TABLE
see article  SEE FULL ARTICLE


Atomic Number76

Atomic SymbolOs

Atomic Weight190.23 amu

GroupTransition, 8

FormSolid

Density @ STP22.59 g/cm3

Melting Point3033 °C (5491.4 °F, 3306.15 °K)

Boiling Point5012 °C (9053.6 °F, 5285.15 °K)

Heat of Fusion57.85 kJ/mol

Heat of Vaporization630 kJ/mol

First Ionization Potential8.7 eV

Electronegativity (on Pauling scale)2.2

Specific Heat Capacity0.130 J/g K

Ground State Electron Configuration5d6 6s2

Oxidation States+3, +4

Stable Isotopes and Natural Abundance on Earth184Os, 0.02%; 186Os, 1.58%; 187Os, 1.6%; 188Os, 13.3%; 189Os, 16.1%; 190Os, 26.4%; 192Os, 41.0%

Selected Radioisotopes191Os, 194Os

Atomic Radius185 pm

Crystal StructureHexagonal

Discovered byTennant, 1803

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