Fermium - Fm
Fermium (Fm)
Fermium is a radioactive actinide produced in very small quantities. It does not have a standard atomic weight; the bracketed value below identifies a representative isotope mass number.
| Atomic number | 100 |
|---|---|
| Representative isotope mass number | [257] |
| Electron configuration | [Rn] 5f12 7s2 |
| Density | not established |
| Melting point | 1527 °C |
| Boiling point | not established |

Uses and applications
Fermium has no applications outside scientific research. It is made in extremely small quantities and studied to understand heavy-element chemistry and nuclear properties.
Fermium and water management
Fermium is not a water-treatment chemical. If present in nuclear or research waste, its isotope and activity must be identified and the material managed as radioactive waste under applicable controls.
Occurrence and environmental context
Fermium is a synthetic actinide with no stable isotopes. Its occurrence outside controlled production is extremely limited. Environmental assessment, if relevant, depends on isotope, activity, chemical form, and the specific source.
Health and safety
Fermium requires specialised radiological controls. Exposure risk depends on isotope, activity, chemical form, and exposure route. Follow applicable radiation-protection procedures and institutional requirements when handling radioactive materials or waste.
Back to the periodic table of elements
Sources and further reading
Element page last reviewed: 24 October 2026 by Lenntech.