| Quantity | Value | Units | Value | Units |
| Atomic number | 51 | |||
| Atomic mass | 121.760(1) | g mole-1 | ||
| Density | 6.69 | g cm-3 | ||
| Mean excitation energy | 487.0 | eV | ||
| Minimum ionization | 1.259 | MeV g-1cm2 | 8.424 | MeV cm-1 |
| Nuclear collision length | 98.9 | g cm-2 | 14.78 | cm |
| Nuclear interaction length | 168.0 | g cm-2 | 25.11 | cm |
| Pion collision length | 123.1 | g cm-2 | 18.40 | cm |
| Pion interaction length | 195.6 | g cm-2 | 29.23 | cm |
| Radiation length | 8.73 | g cm-2 | 1.304 | cm |
| Critical energy | 11.70 | MeV (for e-) | 11.31 | MeV (for e+) |
| Molière radius | 15.81 | g cm-2 | 2.363 | cm |
| Plasma energy |
48.24 | eV | ||
| Muon critical energy | 204. | GeV |