077Transition metal · Group 9 · Period 6
Iridium
Iridium (Ir) is element 77, a transition metal in the d-block — group 9, period 6. It is a solid at room temperature with 6 electron shells (2, 8, 18, 32, 15, 2) and an atomic mass of 192.2173 u.
- Atomic mass
- 192.2 u
- Phase · STP
- solid
- Melting
- 2719 K · 2446 °C
- Boiling
- 4403 K · 4130 °C
- Electronegativity
- 2.2
- Density
- 22.56 g/cm³
Photograph — Unknown authorUnknown author, CC BY 1.0 <https://creativecommons.org/licenses/by/1.0>, via Wikimedia Commons, source: https://images-of-elements.com/iridium.php
Identity
- Atomic number
- 77
- Standard atomic weight
- 192.2 u
- Category
- Transition metal
- Group
- 9
- Period
- 6
- Block
- d-block
- Oxidation states
- +4, +3
Physical properties
- Melting point
- 2719 K · 2446 °C
- Boiling point
- 4403 K · 4130 °C
- Density
- 22.56 g/cm³
- Molar heat capacity
- 25.1 J/(mol·K)
- Atomic radius
- 202 pm
- Electron affinity
- 150.94 kJ/mol
Atomic structure
77protons
115neutrons
77electrons
2valence e⁻
- Noble-gas notation
- [Xe] 4f14 5d7 6s2
- Full configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d7
- Electrons per shell
- 2, 8, 18, 32, 15, 2
Periodic trends
Where Iridium ranks across all 118 elements.
Ionization energies
Energy to remove each successive electron (kJ/mol).
8801
1.6k2
Successive ionization energies (kJ/mol, log scale).
Discovery
- Discovered
- 1803
- Discovered by
- Smithson Tennant
- Named by
- —
- Appearance
- silvery white