| Protactinium | |
| Electrons per shell | 2,8,18,32,20,9,2 |
| Electron Configuration | [Rn] 5f2 6d1 7s2 ![]() |
| Ground state | (4,3/2)11/2 |
| Atomic Volume | 15 cm3 mol-1 |
| Electronegativity | 1.5 |
| Magnetic ordering | No data |
| Mass magnetic susceptibility | 3.25 x 10-8 |
| Molar magnetic susceptibility | 7.509 x 10-9 |
Thermal Properties |
|
| Enthalpy of Atomization | No data. |
| Enthalpy of Fusion | 16.7 kJ mol-1 |
| Enthalpy of Vaporisation | 481 kJ mol-1 |
| Heat Capacity | No data. |
| Thermal Conductivity | 47 W m-1 K-1 |
| Thermal Expansion | No data. |
| Critcal Temperature | No data. |
| Critcal Pressure | No data. |
| Adiabatic index | No data. |
Electrical Properties |
|
| Electrical resistivity | 1.8 x 10-7 Ω m |
| Electrical conductivity | 0.0529 106/cm Ω |
Chemical Properties |
|
| Electrochemical Equivalent | 1.724 g Ah-1 |
| Valence Electron Potential (-eV) | 92 |
| Ionization Potential | |
| 5.89 | |
Energy Levels |
|
| 95.868 KeV | |
| 92.287 KeV | |
| 108.427 KeV | |
| 13.2907 KeV | |
| 13.1222 KeV | |
| 16.702 KeV | |
| 16.024 KeV | |
| 16.9293 KeV | |
| 16.1005 KeV | |
| 19.568 KeV | |
| 19.8832 KeV | |
| 14.942 KeV | |
| 11.3685 KeV | |
Atomic Radii |
|
| 180 pm | |
| No data. | |
| No data. | |
| No data. | |
| 129 pm | |
| 263 pm | |
Ionic Radii (Å) |
||||
| Charge | Coordination | Crystal | Ionic | Key |
| 3 | VI | 1.18 | 1.04 | E |
| 4 | VI | 1.04 | 0.9 | R |
| VIII | 1.15 | 1.01 | ||
| 5 | VI | 0.92 | 0.78 | |
| VIII | 1.05 | 0.91 | ||
| IX | 1.09 | 0.95 | ||
| 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 |
|
| Pa+5 | |
| Pa+3, Pa+4 | |
Ionisation Energies (kJ mol-1) ![]() |
|
| 568 | |
Crystal Structure |
|
| Tetragonal | |
![]() |
a = 392.5 pm |
| b = 392.5 pm | |
| c = 323.8 pm | |
| α = 90° | |
| β = 90° | |
| γ = 90° | |