Atomic number 77
Iridium
Transition metal
Quick facts
- Atomic mass
- 192.22
- Group
- 9
- Period
- 6
- State (STP)
- solid
- Electronegativity
- 2.20
- Common ox. states
- +3, +4
Properties
Electron configuration
[Xe] 4f¹⁴ 5d⁷ 6s²
- Ionization energy
- 880.0 kJ/mol
- Electron affinity
- 151.0 kJ/mol
- Melting point
- 2719.00 K (2445.8 °C)
- Boiling point
- 4701.00 K (4427.9 °C)
How it bonds
The most corrosion-resistant metal known. Common +3 and +4 states. The famous K-Pg-boundary iridium spike is the geological smoking gun for the asteroid impact that ended the dinosaurs — iridium is rare in Earth's crust but common in meteorites.