Osmium

Atomic number

76

Atomic mass (u)

190.2

Category

Transition metal

Standard state

Solid

Melting point

3032.85 °C (3306 K)

Boiling point

5011.85 °C (5285 K)

Density (g/cm³)

22.57

Electronegativity (Pauling)

2.2

Electron configuration

[Xe]6s2 4f14 5d6

Oxidation states

+4, +3

Atomic radius (pm)

216

First ionization energy (eV)

8.7

Discovery & recognition

Discovery year / period (PubChem)

1803

Discovery credited to (RSC)

Smithson Tennant

Date or period recorded by RSC

1803

Discovery place

Not supplied in the structured record; see the RSC history source.

An ancient date does not identify a first human discovery. Different references may date observation, isolation and formal recognition differently.

Natural occurrence & production

The creation of an element’s nuclei and its concentration into terrestrial deposits are different processes. The occurrence note below concerns its presence or production on Earth; it is not a complete account of nucleosynthesis.

“Osmium occurs uncombined in nature and also in the mineral osmiridium (an alloy with iridium).”

Royal Society of Chemistry · occurrence excerpt ↗

Continue the research

Reference values are not product specifications. Blank values have not been estimated. For superheavy elements, some properties and family assignments are theoretical or incompletely measured.