| Rubidium | |
| Electrons per shell | 2,8,18,8,1 |
| Electron Configuration | [Kr] 5s1 |
| Ground state | 2S1/2 |
| Atomic Volume | 55.9 cm3 mol-1 |
| Electronegativity | 0.82 |
| Magnetic ordering | No data |
| Mass magnetic susceptibility | 2.6 x 10-9 |
| Molar magnetic susceptibility | 2.22 x 10-10 |
| Speed of sound | 1300 m s-1 |
 Thermal Properties |
|
| Enthalpy of Atomization | 82 kJ mol-1 @25°C |
| Enthalpy of Fusion | 2.2 kJ mol-1 |
| Enthalpy of Vaporisation | 75.7 kJ mol-1 |
| Heat Capacity | 31.060 J mol-1 K-1 |
| Thermal Conductivity | 58.2 W m-1 K-1 |
| Thermal Expansion | No data. |
| Hardness |
|
| Brinell hardness | 0.216 MPa |
| Mohs hardness | 0.3 |
| Elastic Properties |
|
| Bulk modulus | 2.5 GPa |
| Young's modulus | 2.4 GPa |
| Electrical Properties |
|
| Electrical resistivity | 1.2 x 10-7 Ω m |
| Electrical conductivity | 0.0779 106/cm Ω |
| Chemical Properties |
|
| Electrochemical Equivalent | 3.1888 g Ah-1 |
| Electron Work Function | 2.16 eV |
| Valence Electron Potential (-eV) | 9.47 |
| Ionization Potential | |
 First
|
4.177 |
| Second
|
27.28 |
| Third
|
40 |
| Energy Levels |
|
| Kα1 (intensity 100) |
13.3953 KeV |
| Kα2 (intensity 50) |
13.3358 KeV |
| Kβ1 (intensity 15.8) |
14.9613 KeV |
| Kβ2 (intensity 2.6) |
15.1837 KeV |
| Kβ3 (intensity 7.7) |
14.949 KeV |
| Lα1 (intensity 100) |
1.69413 KeV |
| Lα2 (intensity 10) |
1.69256 KeV |
| Lβ1 (intensity 37.8) |
1.75217 KeV |
| Lβ3 (intensity 3.5) |
1.8273 KeV |
| Lβ4 (intensity 0.2) |
1.8161 KeV |
| Lγ3 (intensity 3) |
1.542 KeV |
| Ll (intensity 4.5) |
1.4829 KeV |
| Atomic Radii |
|
| Empirical
|
235 pm |
| Bohr Radius
|
265 pm |
| Covalent Radius
|
211 pm |
| Van der Waals
|
244 pm |
| Triple covalent
|
No data. |
| Metallic
|
248 pm |
| Oxidation States |
|
| Main
|
Rb-1 (in liquid NH3), Rb+1 |
| Other
|
|
Ionisation Energies (kJ mol-1)  |
|
| M - M+ |
403 |
| M+ - M2+ |
2632 |
| M2+ - M3+ |
3900 |
| M3+ - M4+ |
5080 |
| M4+ - M5+ |
6850 |
| M5+ - M6+ |
8140 |
| M6+ - M7+ |
9570 |
| M7+ - M8+ |
13100 |
| M8+ - M9+ |
14800 |
| M9+ - M10+ |
26740 |
| Vapour Pressure |
||||||
| P (Pa) | 1 | 10 | 100 | 1K | 10K | 100K |
| T (K) | 434 | 486 | 552 | 641 | 769 | 958 |
| Crystal Structure |
|
| Structure
|
Body centred cubic |
 |
a = 558.5 pm |
| b = 558.5 pm | |
| c = 558.5 pm | |
| α = 90° | |
| β = 90° | |
| γ = 90° | |