Curium (Cm)


  • Symbol: Cm
  • Atomic Number: 96
  • Atomic Weight: [247]
  • Element Classification: Actinide
  • Discovered By: Glenn T. Seaborg, Ralph A. James, and Albert Ghiorso
  • Discovery Date: 1944
  • Name Origin: Named after Marie Curie and Pierre Curie, pioneers in the study of radioactivity
  • Density(g/cc): 13.51
  • Melting Point: 1345°C
  • Boiling Point: 3110°C (estimated)
  • Appearance: Silvery metallic, radioactive
  • Atomic Radius(pm): 174 (estimated)


Curium was discovered in 1944 by Glenn T. Seaborg, Ralph A. James, and Albert Ghiorso at the University of California, Berkeley. The discovery was part of their work on the Manhattan Project. Curium was synthesized by bombarding plutonium-239 with alpha particles (helium nuclei) in a cyclotron, which produced curium-242 along with a free neutron. The element was named after Marie and Pierre Curie, renowned for their research on radioactivity, marking a tribute to their contributions to science.

Relation to Other Elements

Curium is a member of the actinide series, sharing characteristics common to this group, such as being radioactive and having multiple oxidation states. It exhibits chemical behavior similar to that of other late actinides and the lanthanide series, with a typical +3 oxidation state in solutions. Curium’s position in the actinide series means it has complex electron configurations and exhibits properties both metallic and radioactive in nature.

Natural Occurrence

Curium does not occur naturally and is produced synthetically in nuclear reactors or particle accelerators through the bombardment of lighter elements with neutrons or charged particles.


Due to its radioactivity and synthetic production, curium’s uses are specialized and mainly related to research:

  • Alpha-particle Source: Curium isotopes, especially curium-244, are used as sources of alpha particles for X-ray spectrometers in planetary science missions, including the Mars rovers, to analyze the chemical composition of rocks and soil.
  • Radioisotope Thermoelectric Generators (RTGs): Curium-244 has been considered as a heat source in RTGs for providing power to spacecraft, satellites, and remote terrestrial applications, although its use is less common compared to plutonium-238.
  • Neutron Source: When mixed with certain other elements, curium can serve as a compact neutron source for use in research and industrial applications.

The discovery of curium expanded the knowledge of synthetic, radioactive elements and honored the legacy of the Curies. While its practical applications are limited by its radioactivity and the complexity of its handling, curium plays a role in scientific research and space exploration, demonstrating the continued importance of synthetic elements in advancing technology and our understanding of the universe.


Americium (Am)

Berkelium (Bk)