Promethium vs Osmium
| Property | Pm Promethium | Os Osmium |
|---|---|---|
| Atomic number | 61 | 76 |
| Symbol | Pm | Os |
| Name | Promethium | Osmium |
| Category | lanthanide | transition-metal |
| Standard Atomic Weight | 145 u | 190.23 u |
| Period | 6 | 6 |
| Group | N/A | 8 |
| Block | s | s |
| Phase at STP | solid | solid |
| Electron configuration | [Xe]6s24f5 | [Xe]6s24f145d6 |
| Oxidation states | [2, 3] | [-4, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8] |
| Electronegativity (Pauling) | N/A | 2.2 |
| Electron affinity | 0.129 eV | 1.1 eV |
| Density | 7260 kg/m³ | 2.258720e+4 kg/m³ |
| Melting point | 1041.85 °C | 3032.85 °C |
| Boiling point | 2999.85 °C | 5011.85 °C |
| Discovery year | 1902 | 1803 |