| Thulium | |
| Electrons per shell | 2,8,18,31,8,2 |
| Electron Configuration | [Xe] 4f13 6s2 |
| Ground state | 2F°7/2 |
| Atomic Volume | 18.1 cm3 mol-1 |
| Electronegativity | 1.25 |
| Magnetic ordering | No data |
| Mass magnetic susceptibility | 1.99 x 10-6 |
| Molar magnetic susceptibility | 3.36179 x 10-7 |
 Thermal Properties |
|
| Enthalpy of Atomization | 247 kJ mol-1 @25°C |
| Enthalpy of Fusion | 18.4 kJ mol-1 |
| Enthalpy of Vaporisation | 247 kJ mol-1 |
| Heat Capacity | 27.03 J mol-1 K-1 |
| Thermal Conductivity | 16.9 W m-1 K-1 |
| Thermal Expansion | 13.3 μm m-1 K-1 |
| Hardness |
|
| Brinell hardness | 471 MPa |
| Vickers hardness | 520 MPa |
| Elastic Properties |
|
| Bulk modulus | 44.5 GPa |
| Poisson ratio | 0.213 |
| Shear modulus | 30.5 GPa |
| Young's modulus | 74.0 GPa |
| Electrical Properties |
|
| Electrical resistivity | 7.0 x 10-7 Ω m |
| Electrical conductivity | 0.015 106/cm Ω |
| Chemical Properties |
|
| Electrochemical Equivalent | 2.101 g Ah-1 |
| Valence Electron Potential (-eV) | 49.7 |
| Ionization Potential | |
 First
|
6.184 |
| Second
|
12.054 |
| Third
|
26.367 |
| Energy Levels |
|
| Kα1 (intensity 100) |
50.7416 KeV |
| Kα2 (intensity 50) |
49.7726 KeV |
| Kβ1 (intensity 24.3) |
57.517 KeV |
| Kβ2 (intensity 9.1) |
58.7551 KeV |
| Kβ3 (intensity 9.7) |
57.3519 KeV |
| Lα1 (intensity 100) |
7.1799 KeV |
| Lα2 (intensity 10) |
7.1331 KeV |
| Lβ1 (intensity 44.5) |
8.101 KeV |
| Lβ2 (intensity 19.5) |
8.468 KeV |
| Lβ3 (intensity 9) |
8.232 KeV |
| Lβ4 (intensity 4) |
8.0239 KeV |
| Lγ1 (intensity 7) |
9.426 KeV |
| Lγ2 (intensity 2.4) |
9.7366 KeV |
| Lγ3 (intensity 2) |
7.307 KeV |
| Ll (intensity 5) |
6.3389 KeV |
| Atomic Radii |
|
| Empirical
|
175 pm |
| Bohr Radius
|
222 pm |
| Covalent Radius
|
No data. |
| Van der Waals
|
No data. |
| Triple covalent
|
No data. |
| Metallic
|
175.9 pm |
| Oxidation States |
|
| Main
|
Tm+3 |
| Other
|
Tm+2 |
Ionisation Energies (kJ mol-1)  |
|
| M - M+ |
596.7 |
| M+ - M2+ |
1163 |
| M2+ - M3+ |
2285 |
| M3+ - M4+ |
4119 |
| Vapour Pressure |
||||||
| P (Pa) | 1 | 10 | 100 | 1K | 10K | 100K |
| T (K) | 1117 | 1235 | 1381 | 1570 | (1821) | (2217) |
| Crystal Structure |
|
| Structure
|
Hexagonal close packed |
 |
a = 353.75 pm |
| b = 353.75 pm | |
| c = 555.46 pm | |
| α = 90° | |
| β = 90° | |
| γ = 120° | |