Element 77
Iridium (Ir)
Iridium (Ir) is element 77 of the periodic table, a transition metal in period 6, group 9 (d-block) with an atomic mass of 192.22 and is a solid at standard conditions.
At a glance
- Atomic number
- 77
- Symbol
- Ir
- Atomic mass
- 192.22 u
- Category
- Transition metals
- Period
- 6
- Group
- 9
- Block
- d-block
- Phase at STP
- solid
Electron structure
- Electron configuration
- 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d7 6s2
- Shorthand configuration
- [Xe] 4f14 5d7 6s2
- Electrons per shell
- 2, 8, 18, 32, 15, 2
- Oxidation states
- -3, -1, +1, +2, +3, +4, +5, +6, +7, +8, +9
Physical properties
- Melting point
- 2719 K
- Boiling point
- 4701 K
- Density
- 22.56 g/cm3
- Phase
- solid
Atomic properties
- Electronegativity (Pauling)
- 2.2
- Atomic radius
- 180 pm
- Covalent radius
- 141 pm
- First ionization energy
- 880 kJ/mol
- Electron affinity
- 151 kJ/mol
Notable isotopes
| Isotope | Mass | Abundance | Stability |
|---|---|---|---|
| Ir-193 | 192.96292 | 62.7% | Stable |
Common uses
- Spark plugs
- Crucibles
- Electrical contacts
- Cancer treatment
Discovery
- Year
- 1803
- Discovered by
- Smithson Tennant
- Country
- England