Fermium (Fm)


  • Symbol: Fm
  • Atomic Number: 100
  • Atomic Weight: [257]
  • Element Classification: Actinide
  • Discovered By: Albert Ghiorso and the Lawrence Berkeley National Laboratory team
  • Discovery Date: 1952
  • Name Origin: Named after Enrico Fermi, renowned physicist
  • Density(g/cc): Not well determined; estimated around 9.7
  • Melting Point: 1527°C (estimated)
  • Boiling Point: Not determined
  • Appearance: Presumed to be a solid metal under normal conditions, but its exact appearance is unknown due to its radioactivity and production in minute amounts
  • Atomic Radius(pm): 186 (estimated)


Fermium was discovered by Albert Ghiorso and a team of scientists at the Lawrence Berkeley National Laboratory in 1952. It was identified among the debris from the first hydrogen bomb test, which took place in the Pacific Ocean at the Enewetak Atoll, part of Operation Ivy. Fermium, along with einsteinium, was a product of the intense neutron flux conditions present during the thermonuclear explosion. The element was named in honor of Enrico Fermi, a pioneering physicist known for his work on nuclear reactions and a key figure in the development of the atomic bomb.

Relation to Other Elements

Fermium is a member of the actinide series, characterized by its radioactive properties and position in the f-block of the periodic table, indicating a filling of the 5f electron orbital. Like other actinides, fermium can exhibit multiple oxidation states, with +2 and +3 being the most common in its compounds. However, the chemical and physical properties of fermium are not extensively studied due to the element’s high radioactivity and the challenges associated with producing it in significant quantities.

Natural Occurrence

Fermium does not occur naturally on Earth and is produced synthetically in very small amounts. It is typically created in nuclear reactors or during the detonation of nuclear weapons through a series of neutron capture reactions involving lighter actinides.


Fermium’s applications are limited to research due to its scarcity and radioactivity:

  • Scientific Research: The primary use of fermium is in basic scientific research to study the properties of actinide elements and investigate the synthesis of heavy elements. Experiments with fermium have helped scientists understand more about its nuclear structure and chemical behavior.
  • Synthesis of Heavier Elements: Fermium serves as a target material in particle accelerators for the production of heavier elements, including those beyond fermium in the periodic table, by bombarding it with charged particles.

The discovery of fermium contributed to the understanding of nuclear processes and the structure of heavy elements. While its practical uses are limited by its radioactive nature and the difficulty of its production, fermium remains an area of interest in scientific research, particularly in the fields of nuclear physics and chemistry.


Einsteinium (Es)

Mendelevium (Md)