Rhenium Iridium

Osmium (Os)

From Wikipedia, the free encyclopediaOsmium (from Greek osme (ὀσμή) meaning "smell") is a chemical element with symbol Os and atomic number 76. It is a hard, brittle, bluish-white transition metal in the platinum group that is found as a trace element in alloys, mostly in platinum ores. Osmium is the densest naturally occurring element, with a density of 22.59 g/cm3.

Osmium in the periodic table

Symbol

Atomic number

Group

Period

Block

Element category

Transition Metal

Physical properties

Phase at STP

Solid

Density

22.59 g/cm³

Atomic weight

190.233 u

Melting point

3306 K
3032.85 °C
5491.13 °F

Boiling point

5285 K
5011.85 °C
9053.33 °F

Atomic properties

Electronegativity (Pauling Scale)

2.2

Electron affinity

103.99 kJ/mol

Oxidation states

−4, −2, −1, 0, +1, +2, +3, +4, +5, +6, +7, +8
(a mildly acidic oxide)

Ionization energies

1	840 kJ/mol
2	1600 kJ/mol

Electron configuration

Elektronkonfiguration (shorthand)

[Xe] 4f¹⁴ 5d⁶ 6s²

Electron configuration

1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d⁶ 6s²

Electrons per shell

2, 8, 18, 32, 14, 2

History

Discovered

1803

Discovered by

Smithson Tennant