Fermium is a synthetic element named after Enrico Fermi, the heaviest element that can be formed by neutron bombardment.
Core Principles & Analysis
Fermium, named for Enrico Fermi, was also found in fallout from the 1952 'Ivy Mike' test, where uranium nuclei had captured as many as 17 neutrons within seconds of the blast.
Fermium-257, with a 100.5-day half-life, is the heaviest nuclide that can be produced by neutron capture in reactors; every heavier element must be built in particle accelerators.
The 'fermium gap' blocks any neutron-capture route to heavier elements, because fermium-258 destroys itself by spontaneous fission with a half-life of only about 370 microseconds.