Iridium
A corrosion-proof metal enriched in asteroid impact layers.
Inside the Iridium atom
Switch between Bohr and Quantum Cloud modes to compare a simple teaching model with a more realistic probability-based view, and follow the guided tour to explore the Iridium atom step by step.
Electron configuration
[Xe] 4f14 5d7 6s2
A neutral Iridium atom has 77 electrons (equal to its proton count). Choosing a different isotope above changes only the neutron count.
Shell distribution
Electrons fill inner shells before outer ones; the outermost (valence) shell drives the element's chemistry.
Physical & atomic properties
- State (room temp)
- Solid
- Melting point
- 2739 K (2466 °C)
- Boiling point
- 4701 K (4428 °C)
- Density
- 22.56 g/cm³
- Electronegativity
- 2.2 Pauling
- Atomic radius
- 135 pm
- 1st ionization energy
- 880 kJ/mol
- Category
- Transition metals
Discovery & naming
- Discovered
- 1803
- Discovered by
- Smithson Tennant
- Origin of name
- Latin 'iris', the rainbow.
Notable uses
Long-life spark plugs and hard crucibles.
Where Iridium comes from
Neutron star mergers
An r-process metal. The iridium layer marking the dinosaur extinction is asteroid material — itself stellar debris.
Simplified origin map — many elements form through more than one astrophysical pathway.
Summary
- Atomic number
- 77
- Atomic mass
- 192.22
- Category
- Transition metals
- Group · Period
- 9 · 6
- Block
- d-block
- Shells
- 2 · 8 · 18 · 32 · 15 · 2