Osmium
Osmium (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.
A stylized shell model. Electrons are quantum objects, not particles following these literal paths. Sizes and motion are illustrative.
54 is the [Xe] core total across five shells.
At a glance
- Atomic number
- 76
- Atomic mass
- 190.233 u
- Phase
- Solid
- Density
- 22.59 g/cm³
- Melting point
- 3,306 K
- Boiling point
- 5,285 K
- First ionization energy
- 840 kJ/mol
- Electronegativity
- 2.2
- Electron affinity
- 103.99 kJ/mol
- Molar heat capacity
- 24.7 J/(mol·K)
- Period
- 6
- Appearance
- silvery, blue cast
Conditions and isotopes affect measured properties. Some properties of short-lived elements are predicted. Electronegativity uses the Pauling scale.
Keep exploring
Explore the stories, imagery, and reference data in more depth. Properties with no value in the reference are marked unavailable.