Iridium
Iridium is a chemical element with symbol Ir and atomic number 77. A very hard, brittle, silvery-white transition metal of the platinum group, iridium is generally credited with being the second densest element (after osmium) based on measured density, although calculations involving the space lattices of the elements show that iridium is denser. It is also the most corrosion-resistant metal, even at temperatures as high as 2000 °C. Although only certain molten salts and halogens are corrosive to solid iridium, finely divided iridium dust is much more reactive and can be flammable.
A stylized shell model. Electrons are quantum objects, not particles following these literal paths. Sizes and motion are illustrative.
54 is the [Xe] core total across five shells.
At a glance
- Atomic number
- 77
- Atomic mass
- 192.2173 u
- Phase
- Solid
- Density
- 22.56 g/cm³
- Melting point
- 2,719 K
- Boiling point
- 4,403 K
- First ionization energy
- 880 kJ/mol
- Electronegativity
- 2.2
- Electron affinity
- 150.94 kJ/mol
- Molar heat capacity
- 25.1 J/(mol·K)
- Period
- 6
- Appearance
- silvery white
Conditions and isotopes affect measured properties. Some properties of short-lived elements are predicted. Electronegativity uses the Pauling scale.
Keep exploring
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