Rhodium (Rh)
Rhodium (Rh) is element 45, a transition metal. Atomic mass 102.90549, configuration [Kr] 4d⁸ 5s¹. Properties, isotopes, oxidation states, uses and history, with an interactive 3D atom model.
Key facts
| Atomic number | 45 |
|---|---|
| Symbol | Rh |
| Standard atomic weight | 102.90549(2) |
| Category | Transition Metal |
| Group | 9 |
| Period | 5 |
| State at room temperature | Solid |
| Electron configuration | [Kr] 4d⁸ 5s¹ |
| Valence electrons | 1 (Variable) |
| Common oxidation states | +3 |
| Common ions | No common ions |
| Electronegativity (Pauling) | 2.28 |
| First ionization energy | 720 kJ/mol |
| Electron affinity | 109.7 kJ/mol |
| Atomic radius | 173 pm |
| Density | 12.4 g/cm³ |
| Melting point | 1963°C |
| Boiling point | 3695°C |
| Specific heat | 0.243 J/(g·°C) |
Natural isotopes
- Rh-103: Stable
Common uses
- Catalytic converters (80% of use)
- Jewelry plating (gold finish)
Where it matters
- Automotive Industry (Catalytic converters for NOx reduction)
Hazards
- Compounds are toxic/carcinogenic
- metal is inert
History
| Discovered | 1803 |
|---|---|
| Discovered by | William Hyde Wollaston |
| Name | From Greek rhodon (rose, due to salt color) |