An element born in the fire of the first hydrogen bomb. Fermium is named after Enrico Fermi — the physicist who started the world's first nuclear reactor. This Italian-born genius changed the course of history, and now his name is written forever into the periodic table at number 100.
Fermium does not exist in nature. It was first found in 1952 among the radioactive debris of the Ivy Mike test — the most powerful thermonuclear explosion of its time. The discovery was kept secret for three years. Today fermium is produced in nuclear reactors, but only micrograms at a time. It does not last long and quickly decays.
Fermium is the last element that can be produced through neutron capture. Anything heavier decays faster than it can absorb the next neutron. That makes fermium a frontier — the boundary between two different methods of element synthesis. Its most stable isotope, Fm-257, survives just 100 days. Scientists work with micrograms and must move fast before the atoms decay.
Fermium is extraordinarily radioactive. It emits alpha particles and gamma rays, and some isotopes undergo spontaneous fission, releasing neutrons. If ingested, it accumulates in bones. It can only be handled remotely, inside specialized hot cells with thick shielding.
Fermium was born in nuclear fire. It was first found in the debris after the Ivy Mike hydrogen bomb test in 1952 at the Enewetak Atoll.
The discovery of fermium was kept secret for 3 years. The world only learned about element 100 in 1955, after nuclear test data was declassified.
Fermium is the heaviest element that can be 'grown' in a reactor. Everything heavier must be created in accelerators by smashing atoms into atoms.
The longest-lived isotope, Fm-257, decays in 100 days. Scientists have just a few months for all their experiments — then the sample simply vanishes.
Enrico Fermi, the element's namesake, built the first nuclear reactor beneath the bleachers of the University of Chicago's football stadium in 1942.
| Isotope | Mass (u) | Abundance | Half-life | Decay |
|---|---|---|---|---|
255Fm☢ | 255.089962 | synthetic | 20.07 hours | α |
257Fm☢ | 257.095105 | synthetic | 100.5 days | α |
First hydrogen bomb test debris