Iridium (Ir)
Iridium is the chemical element with atomic number 77 and symbol Ir. It is a transition metal in period 6, group 9, with a standard atomic weight of 192.22 u.
Key facts
- Z
- 77
- Atomic weight
- 192.22 u
- Category
- transition metal
- State at 298 K
- Solid
- Occurrence
- primordial
- Discovered
- 1803
- CAS
- 7439-88-5
Measured properties
| Property | Value | Source |
|---|---|---|
| Electronegativity | 2.2 | National Center for Biotechnology Information (NIH) |
| Melting point | 2,719 K | National Center for Biotechnology Information (NIH) |
| Boiling point | 4,701 K | National Center for Biotechnology Information (NIH) |
| Density stp | 22.42 g/cm³ | National Center for Biotechnology Information (NIH) |
| Atomic radius empirical | 202 pm | National Center for Biotechnology Information (NIH) |
| Ionization energy 1st | 878 kJ/mol | National Center for Biotechnology Information (NIH) |
| Electron affinity | 151 kJ/mol | National Center for Biotechnology Information (NIH) |
Electron configuration
- Noble gas notation
- [Xe] 4f¹⁴ 5d⁷ 6s²
- Full notation
- 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d⁷ 6s²
- Electrons per shell
- 2, 8, 18, 32, 15, 2