|
|
| Protactinium | |
| Electron Configuration | 2,8,18,32,20,9,2 |
| Electron Configuration | [Rn] 5f2 6d1 7s2 |
| Ground state | (4,3/2)11/2 |
| Atomic Volume | 15 g/cm3 |
| 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. |
| Electrical Properties |
|
| Electrical resistivity | 1.8 x 10-7 Ω m |
| Electrical conductivity | No data. |
| Chemical Properties |
|
| Electrochemical Equivalent | 1.724 g Ah-1 |
| Valence Electron Potential (-eV) | 92 |
| Ionization Potential | |
 First
|
5.89 |
| Energy Levels |
|
| Kα1 (intensity 0) |
95.868 KeV |
| Kα2 (intensity 0) |
92.287 KeV |
| Kβ1 (intensity 0) |
108.427 KeV |
| Lα1 (intensity 100) |
13.2907 KeV |
| Lα2 (intensity 10) |
13.1222 KeV |
| Lβ1 (intensity 38) |
16.702 KeV |
| Lβ2 (intensity 14) |
16.024 KeV |
| Lβ3 (intensity 2) |
16.9293 KeV |
| Lβ4 (intensity 2) |
16.1005 KeV |
| Lγ1 (intensity 8) |
19.568 KeV |
| Lγ2 (intensity 2.7) |
19.8832 KeV |
| Lγ3 (intensity 2) |
14.942 KeV |
| Ll (intensity 6) |
11.3685 KeV |
| Atomic Radii |
|
| Empirical
|
180 pm |
| Bohr Radius
|
No data. |
| Covalent Radius
|
No data. |
| Van der Waals
|
No data. |
| Triple covalent
|
129 pm |
| Metallic
|
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 |
|
| Main
|
Pa+5 |
| Other
|
Pa+3, Pa+4 |
Ionisation Energies (kJ mol-1)  |
|
| M - M+ |
568 |
| Crystal Structure |
|
| Structure
|
Tetragonal |
 |
a = 392.5 pm |
| b = 392.5 pm | |
| c = 323.8 pm | |
| α = 90° | |
| β = 90° | |
| γ = 90° | |