NO. 076Transition

Os

Osmium

Osmium is the densest naturally occurring element and is used in wear-resistant alloys.

Crystal Structure

Hexagonal close-packed (hcp)

Atomic Mass190.23 u

Density22.59 g/cm³

Melting Point3306 K

Boiling Point5285 K

Atomic Radius135 pm

Electronegativity2.2

Ionization Energy840 kJ/mol

Electron Affinity106 kJ/mol

Bonding TypeMetallic

Oxidation States2, 3, 4, 6, 8

Acid/BaseBasic

ReactivityLow

Electron Configuration

[Xe] 4f14 5d6 6s2

Discovered BySmithson Tennant

Year1803

Known Isotopes

Os-184Os-186Os-187Os-188Os-189Os-190Os-192