|
|
| Caesium | |
| Electron Configuration | 2,8,18,18,8,1 |
| Electron Configuration | [Xe] 6s1 |
| Ground state | 2S1/2 |
| Atomic Volume | 71.07 g/cm3 |
| Electronegativity | 0.79 |
| Magnetic ordering | No data |
| Mass magnetic susceptibility | -2.8 x 10-9 |
| Molar magnetic susceptibility | -3.72 x 10-10 |
 Thermal Properties |
|
| Enthalpy of Atomization | 78.2 kJ mol-1 @25°C |
| Enthalpy of Fusion | 2.09 kJ mol-1 |
| Enthalpy of Vaporisation | 66.5 kJ mol-1 |
| Heat Capacity | 32.210 J mol-1 K-1 |
| Thermal Conductivity | 35.9 W m-1 K-1 |
| Thermal Expansion | 97 μm m-1 K-1 |
| Hardness |
|
| Brinell hardness | 0.14 MPa |
| Mohs hardness | 0.2 |
| Elastic Properties |
|
| Bulk modulus | 1.6 GPa |
| Young's modulus | 1.7 GPa |
| Electrical Properties |
|
| Electrical resistivity | 2.0 x 10-7 Ω m |
| Electrical conductivity | No data. |
| Chemical Properties |
|
| Electrochemical Equivalent | 4.9587 g Ah-1 |
| Electron Work Function | 2.14 eV |
| Valence Electron Potential (-eV) | 8.62 |
| Ionization Potential | |
 First
|
3.894 |
| Second
|
25.1 |
| Energy Levels |
|
| Kα1 (intensity 100) |
30.9728 KeV |
| Kα2 (intensity 50) |
30.6251 KeV |
| Kβ1 (intensity 20.5) |
34.9869 KeV |
| Kβ2 (intensity 6.3) |
35.8152 KeV |
| Kβ3 (intensity 8.8) |
34.9121 KeV |
| Lα1 (intensity 100) |
4.2865 KeV |
| Lα2 (intensity 10) |
4.2722 KeV |
| Lβ1 (intensity 49) |
4.6198 KeV |
| Lβ2 (intensity 17) |
4.9359 KeV |
| Lβ3 (intensity 9) |
4.7167 KeV |
| Lβ4 (intensity 4) |
4.6488 KeV |
| Lγ1 (intensity 6) |
5.2804 KeV |
| Lγ2 (intensity 3.5) |
5.5462 KeV |
| Lγ3 (intensity 2) |
4.14 KeV |
| Ll (intensity 4) |
3.7976 KeV |
| Atomic Radii |
|
| Empirical
|
260 pm |
| Bohr Radius
|
298 pm |
| Covalent Radius
|
225 pm |
| Van der Waals
|
No data. |
| Triple covalent
|
No data. |
| Metallic
|
265 pm |
| Ionic Radii (Å) |
||||
| Charge | Coordination | Crystal | Ionic | Key |
| 1 | VI | 1.81 | 1.67 | |
| VIII | 1.88 | 1.74 | ||
| IX | 1.92 | 1.78 | ||
| X | 1.95 | 1.81 | ||
| XI | 1.99 | 1.85 | ||
| XII | 2.02 | 1.88 | ||
| 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
|
Cs-1, Cs+1 |
| Other
|
|
Ionisation Energies (kJ mol-1)  |
|
| M - M+ |
375.7 |
| M+ - M2+ |
2420 |
| M2+ - M3+ |
3400 |
| M3+ - M4+ |
4400 |
| M4+ - M5+ |
6000 |
| M5+ - M6+ |
7100 |
| M6+ - M7+ |
8300 |
| M7+ - M8+ |
11300 |
| M8+ - M9+ |
12700 |
| M9+ - M10+ |
23700 |
| Vapour Pressure |
||||||
| P (Pa) | 1 | 10 | 100 | 1K | 10K | 100K |
| T (K) | 418 | 469 | 534 | 623 | 750 | 940 |
| Crystal Structure |
|
| Structure
|
Body centred cubic |
 |
a = 614.1 pm |
| b = 614.1 pm | |
| c = 614.1 pm | |
| α = 90° | |
| β = 90° | |
| γ = 90° | |