|
|
| Rhodium | |
| Electron Configuration | 2,8,18,16,1 |
| Electron Configuration | [Kr] 4d8 5s1 |
| Ground state | 4F9/2 |
| Atomic Volume | 8.3 g/cm3 |
| Electronegativity | 2.28 |
| Magnetic ordering | No data |
| Mass magnetic susceptibility | 1.32 x 10-8 |
| Molar magnetic susceptibility | 1.358 x 10-9 |
| Speed of sound | 4700 m s-1 |
 Thermal Properties |
|
| Enthalpy of Atomization | 556.5 kJ mol-1 @25°C |
| Enthalpy of Fusion | 21.55 kJ mol-1 |
| Enthalpy of Vaporisation | 494.3 kJ mol-1 |
| Heat Capacity | 24.98 J mol-1 K-1 |
| Thermal Conductivity | 150 W m-1 K-1 |
| Thermal Expansion | 8.2 μm m-1 K-1 |
| Hardness |
|
| Brinell hardness | 1100 MPa |
| Mohs hardness | 6.0 |
| Vickers hardness | 1246 MPa |
| Elastic Properties |
|
| Bulk modulus | 380 GPa |
| Poisson ratio | 0.26 |
| Shear modulus | 150 GPa |
| Young's modulus | 275 GPa |
| Electrical Properties |
|
| Electrical resistivity | 4.3 x 10-8 Ω m |
| Electrical conductivity | No data. |
| Chemical Properties |
|
| Electrochemical Equivalent | .2798 g Ah-1 |
| Electron Work Function | 4.98 eV |
| Valence Electron Potential (-eV) | 64 |
| Ionization Potential | |
 First
|
7.46 |
| Second
|
18.08 |
| Third
|
31.06 |
| Incompatibilities | Chlorine trifluoride (ClF3), oxygen difluoride (OF2). |
| Flammability |
|
| Non-combustible solid (except as dust)
|
| Energy Levels |
|
| Kα1 (intensity 100) |
20.2161 KeV |
| Kα2 (intensity 50) |
20.0737 KeV |
| Kβ1 (intensity 17.9) |
22.7236 KeV |
| Kβ2 (intensity 4.2) |
23.1683 KeV |
| Kβ3 (intensity 8.2) |
22.6952 KeV |
| Lα1 (intensity 100) |
2.69674 KeV |
| Lα2 (intensity 10) |
2.69205 KeV |
| Lβ1 (intensity 42) |
2.83441 KeV |
| Lβ2 (intensity 6) |
3.0013 KeV |
| Lβ3 (intensity 5) |
2.9139 KeV |
| Lβ4 (intensity 4) |
2.8903 KeV |
| Lγ1 (intensity 1.5) |
3.1438 KeV |
| Lγ2 (intensity 0.6) |
3.3612 KeV |
| Lγ3 (intensity 2) |
2.519 KeV |
| Ll (intensity 4.5) |
2.3731 KeV |
| Atomic Radii |
|
| Empirical
|
135 pm |
| Bohr Radius
|
173 pm |
| Covalent Radius
|
135 pm |
| Van der Waals
|
No data. |
| Triple covalent
|
106 pm |
| Metallic
|
134 pm |
| Ionic Radii (Å) |
||||
| Charge | Coordination | Crystal | Ionic | Key |
| 3 | VI | 0.805 | 0.665 | R |
| 4 | VI | 0.74 | 0.6 | RM |
| 5 | VI | 0.69 | 0.55 | |
| R, From r3 vs V plots. |
| C, Calculated from bond length - bond strength equations. |
| E, Estimated. |
| *, Most Reliable. |
| M, From Metallic Oxides. |
| A, Ahrens (1952) Ionic radius. |
| P, Pauling's (1960) Crystal Radius. |
| Oxidation States |
|
| Main
|
Rh+3 |
| Other
|
Rh-1, Rh0, Rh+1, Rh+2, Rh+4, Rh+5, Rh+6 |
Ionisation Energies (kJ mol-1)  |
|
| M - M+ |
720 |
| M+ - M2+ |
1744 |
| M2+ - M3+ |
2997 |
| M3+ - M4+ |
4400 |
| M4+ - M5+ |
6500 |
| M5+ - M6+ |
8200 |
| M6+ - M7+ |
10100 |
| M7+ - M8+ |
12200 |
| M8+ - M9+ |
14200 |
| M9+ - M10+ |
22000 |
| Vapour Pressure |
||||||
| P (Pa) | 1 | 10 | 100 | 1K | 10K | 100K |
| T (K) | 2288 | 2496 | 2749 | 3063 | 3405 | 3997 |
| Crystal Structure |
|
| Structure
|
Cubic close packed |
 |
a = 380.34 pm |
| b = 380.34 pm | |
| c = 380.34 pm | |
| α = 90° | |
| β = 90° | |
| γ = 90° | |