Promethium vs Holmium
| Property | Pm Promethium | Ho Holmium |
|---|---|---|
| Atomic number | 61 | 67 |
| Symbol | Pm | Ho |
| Name | Promethium | Holmium |
| Category | lanthanide | lanthanide |
| Standard Atomic Weight | 145 u | 164.93033 u |
| Period | 6 | 6 |
| Group | N/A | N/A |
| Block | s | s |
| Phase at STP | solid | solid |
| Electron configuration | [Xe]6s24f5 | [Xe]6s24f11 |
| Oxidation states | [2, 3] | [0, 1, 2, 3] |
| Electronegativity (Pauling) | N/A | 1.23 |
| Electron affinity | 0.129 eV | 0.338 eV |
| Density | 7260 kg/m³ | 8800 kg/m³ |
| Melting point | 1041.85 °C | 1473.85 °C |
| Boiling point | 2999.85 °C | 2699.85 °C |
| Discovery year | 1902 | 1878 |