Niobium vs Promethium
| Property | Nb Niobium | Pm Promethium |
|---|---|---|
| Atomic number | 41 | 61 |
| Symbol | Nb | Pm |
| Name | Niobium | Promethium |
| Category | transition-metal | lanthanide |
| Standard Atomic Weight | 92.90637 u | 145 u |
| Period | 5 | 6 |
| Group | 5 | N/A |
| Block | s | s |
| Phase at STP | solid | solid |
| Electron configuration | [Kr]5s14d4 | [Xe]6s24f5 |
| Oxidation states | [-3, -1, 0, 1, 2, 3, 4, 5] | [2, 3] |
| Electronegativity (Pauling) | 1.6 | N/A |
| Electron affinity | 0.893 eV | 0.129 eV |
| Density | 8570 kg/m³ | 7260 kg/m³ |
| Melting point | 2476.85 °C | 1041.85 °C |
| Boiling point | 4743.85 °C | 2999.85 °C |
| Discovery year | 1801 | 1902 |