Iridium

Atomic number

77

Atomic mass (u)

192.22

Category

Transition metal

Standard state

Solid

Melting point

2445.85 °C (2719 K)

Boiling point

4427.85 °C (4701 K)

Density (g/cm³)

22.42

Electronegativity (Pauling)

2.2

Electron configuration

[Xe]6s2 4f14 5d7

Oxidation states

+4, +3

Atomic radius (pm)

202

First ionization energy (eV)

9.1

Discovery & recognition

Discovery year / period (PubChem)

1803

Discovery credited to (RSC)

Smithson Tennant

Date or period recorded by RSC

1803

Discovery place

London, United Kingdom

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.

“Iridium is one of the rarest elements on Earth.”

Royal Society of Chemistry · occurrence excerpt ↗

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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.