|
|
| Lanthanum | |
| Electron Configuration | 2,8,18,18,9,2 |
| Electron Configuration | [Xe] 5d1 6s2 |
| Ground state | 2D3/2 |
| Atomic Volume | 20.73 g/cm3 |
| Electronegativity | 1.1 |
| Magnetic ordering | No data |
| Mass magnetic susceptibility | 1.1 x 10-8 |
| Molar magnetic susceptibility | 1.528 x 10-9 |
| Speed of sound | 2475 m s-1 |
 Thermal Properties |
|
| Enthalpy of Atomization | 431 kJ mol-1 @25°C |
| Enthalpy of Fusion | 10.04 kJ mol-1 |
| Enthalpy of Vaporisation | 402.1 kJ mol-1 |
| Heat Capacity | 27.11 J mol-1 K-1 |
| Thermal Conductivity | 13.4 W m-1 K-1 |
| Thermal Expansion | 12.1 μm m-1 K-1 |
| Hardness |
|
| Brinell hardness | 363 MPa |
| Mohs hardness | 2.5 |
| Vickers hardness | 491 MPa |
| Elastic Properties |
|
| Bulk modulus | 27.9 GPa |
| Poisson ratio | 0.280 |
| Shear modulus | 14.3 GPa |
| Young's modulus | 36.6 GPa |
| Electrical Properties |
|
| Electrical resistivity | 6.1 x 10-7 Ω m |
| Electrical conductivity | No data. |
| Chemical Properties |
|
| Electrochemical Equivalent | 1.7275 g Ah-1 |
| Electron Work Function | 3.5 eV |
| Valence Electron Potential (-eV) | 40.71 |
| Ionization Potential | |
 First
|
5.58 |
| Second
|
11.059 |
| Third
|
19.174 |
| Energy Levels |
|
| Kα1 (intensity 100) |
33.4418 KeV |
| Kα2 (intensity 50) |
33.0341 KeV |
| Kβ1 (intensity 21.1) |
37.801 KeV |
| Kβ2 (intensity 6.7) |
38.7215 KeV |
| Kβ3 (intensity 8.9) |
37.7144 KeV |
| Lα1 (intensity 100) |
4.65097 KeV |
| Lα2 (intensity 10) |
4.63423 KeV |
| Lβ1 (intensity 49) |
5.0421 KeV |
| Lβ2 (intensity 18.5) |
5.3835 KeV |
| Lβ3 (intensity 9) |
5.1436 KeV |
| Lβ4 (intensity 4) |
5.0623 KeV |
| Lγ1 (intensity 6.2) |
5.7885 KeV |
| Lγ2 (intensity 2.6) |
6.0595 KeV |
| Lγ3 (intensity 2) |
4.523 KeV |
| Ll (intensity 4.5) |
4.123 KeV |
| Atomic Radii |
|
| Empirical
|
195 pm |
| Bohr Radius
|
No data. |
| Covalent Radius
|
169 pm |
| Van der Waals
|
No data. |
| Triple covalent
|
139 pm |
| Metallic
|
187 pm |
| Ionic Radii (Å) |
||||
| Charge | Coordination | Crystal | Ionic | Key |
| 3 | VI | 1.172 | 1.032 | R |
| VII | 1.24 | 1.1 | ||
| VIII | 1.3 | 1.16 | R | |
| IX | 1.356 | 1.216 | R | |
| X | 1.41 | 1.27 | ||
| XII | 1.5 | 1.36 | C | |
| 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
|
La+3 |
| Other
|
|
Ionisation Energies (kJ mol-1)  |
|
| M - M+ |
538.1 |
| M+ - M2+ |
1067 |
| M2+ - M3+ |
1850 |
| M3+ - M4+ |
4819 |
| M4+ - M5+ |
6400 |
| M5+ - M6+ |
7600 |
| M6+ - M7+ |
9600 |
| M7+ - M8+ |
11000 |
| M8+ - M9+ |
12400 |
| M9+ - M10+ |
15900 |
| Vapour Pressure |
||||||
| P (Pa) | 1 | 10 | 100 | 1K | 10K | 100K |
| T (K) | 2005 | 2208 | 2458 | 2772 | 3178 | 3726 |
| Crystal Structure |
|
| Structure
|
Hexagonal close packed |
 |
a = 377.2 pm |
| b = 377.2 pm | |
| c = 1214.4 pm | |
| α = 90° | |
| β = 90° | |
| γ = 120° | |