Iridium (Ir)
Iridium is element 77, a transition metal in period 6, group 9 of the periodic table. At room temperature it is a solid.
Electron configuration [Xe] 4f14 5d7 6s2
Electrons per shell 2, 8, 18, 32, 15, 2
Iridium data
| Atomic number | 77 |
|---|---|
| Symbol | Ir |
| Atomic mass | 192.217 u |
| Category | Transition metal |
| Group | 9 |
| Period | 6 |
| Block | d |
| State at 25 °C | solid |
| Melting point | 2739 K (2465.9 °C) |
| Boiling point | 4701 K (4427.9 °C) |
| Density | 22.65 g/cm³ |
| Electronegativity (Pauling) | 2.2 |
| Atomic radius | 137 pm |
| 1st ionization energy | 880 kJ/mol |
| Electron affinity | -151 kJ/mol |
| Oxidation states | -3, -1, +1, +2, +3, +4, +5, +6 |
| Common ion charge | 4+ |
| Discovered | 1803 |
Orbital diagram
Each box is one orbital holding up to two electrons of opposite spin. Following Hund’s rule, electrons spread out singly across a subshell before pairing.
Work through iridium’s configuration and its ions →
Where iridium sits
Iridium belongs to the transition metals. Its Pauling electronegativity of 2.2 is mid-range; see the electronegativity chart and periodic trends for context. To use its mass in a calculation, try the molar mass calculator.
Iridium FAQ
What is the electron configuration of iridium?
Iridium (Z = 77) has the configuration 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d7 6s2. In noble-gas shorthand that is [Xe] 4f14 5d7 6s2.
How many valence electrons does iridium have?
9 (2 outer s + 7 d electrons; 2 in the outermost shell).
What is the atomic mass of iridium?
The standard atomic weight of iridium is 192.217 u, so one mole weighs 192.217 g.
Is iridium a metal?
Yes. Iridium is a transition metal.
What is the charge of a iridium ion?
Iridium most commonly forms Ir4+.