Iridium vs Actinium
| Property | Ir Iridium | Ac Actinium |
|---|---|---|
| Atomic number | 77 | 89 |
| Symbol | Ir | Ac |
| Name | Iridium | Actinium |
| Category | transition-metal | actinide |
| Standard Atomic Weight | 192.217 u | 227 u |
| Period | 6 | 7 |
| Group | 9 | N/A |
| Block | s | s |
| Phase at STP | solid | solid |
| Electron configuration | [Xe]6s24f145d7 | [Rn]7s26d1 |
| Oxidation states | [-3, -2, -1, 1, 2, 3, 4, 5, 6, 7, 8, 9] | [3] |
| Electronegativity (Pauling) | 2.2 | 1.1 |
| Electron affinity | 1.565 eV | 0.35 eV |
| Density | 2.256220e+4 kg/m³ | 1.007000e+4 kg/m³ |
| Melting point | 2445.85 °C | 1050.85 °C |
| Boiling point | 4427.85 °C | 3197.85 °C |
| Discovery year | 1803 | 1899 |