NO. 077Transition

Ir

Iridium

Iridium is one of the most corrosion-resistant metals and is used in spark plugs and crucibles.

Crystal Structure

Face-centered cubic (fcc)

Atomic Mass192.22 u

Density22.56 g/cm³

Melting Point2719 K

Boiling Point4701 K

Atomic Radius136 pm

Electronegativity2.2

Ionization Energy880 kJ/mol

Electron Affinity151 kJ/mol

Bonding TypeMetallic

Oxidation States3, 4

Acid/BaseBasic

ReactivityLow

Electron Configuration

[Xe] 4f14 5d7 6s2

Discovered BySmithson Tennant

Year1803

Known Isotopes

Ir-191Ir-193