| Atomic Mass | Mass Excess |
| 257.095098855347 amu | 88.584 MeV |
| Level energy (MeV) | Spin & parity | Half-life | Mode of decay | Branch ratio (%) | Decay energy (MeV) |
| Ground state | (9/2+) | 100.5 D 0.2 | A | 99.79 | 6.864 |
| Ground state | (9/2+) | 100.5 D 0.2 | SF | .21 | 0 |
| Decay mode | Half-life | Gamma-ray energy (keV) | Intensity (%) |
| A | 100.5 D 0.2 | 61.60 | 1.45+- 0.08 |
| A | 100.5 D 0.2 | 104.40 | 0.62+- 0.05 |
| A | 100.5 D 0.2 | 179.40 | 8.7+- 0.7 |
| A | 100.5 D 0.2 | 241.00 | 11.0+- 0.6 |