| Quantity | Value | Units | |
| Atomic number | 87 | n | |
| Atomic mass | (223.019736) | g mole-1 | |
| Density (20° C, 1 atm): | Unknown | g cm-3 | |
| Radiation length | Pending | g cm-2 | |
| Nuclear collision length | Pending | g cm-2 | |
| Nuclear interaction length | Pending | g cm-2 | |
| Critical energy (e-) | Pending | MeV | |
| Molière radius | Pending | g cm-2 | |
| Muon critical energy | Pending | GeV |