Curium Facts (Cm or Atomic Number 96)

Curium Chemical & Physical Properties

Curium element data

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Curium is a radioactive element with atomic number 96 and element symbol Cm. It is a dense, silver metal in the actinide series that glows purple in the dark. It is named for Marie and Pierre Curie – pioneers in radioactivity research.

Curium Basic Facts

Atomic Number: 96

Symbol: Cm

Atomic Weight: 247.0703

Discovery: G.T. Seaborg, R.A. James, A. Ghiorso, 1944 (United States). Because of World War II, the discovery remained a secret until November 1947.

Electron Configuration: [Rn] 5f7 6d1 7s2

Biological Role: Like the other actinides, curium presents a radiological hazard. Curium accumulates in the bones, liver, and lungs. It is primarily an alpha particle emitter and can cause cancer.

Curium Physical Data

Atomic Weight: 247.0703

Element Classification: Radioactive Rare Earth Element (Actinide Series)

Name Origin: Named in honor of Pierre and Marie Curie.

Density (g/cc): 13.51

Melting Point (K): 1340

Appearance: silvery, malleable, synthetic radioactive metal

Atomic Radius (pm): 299

Atomic Volume (cc/mol): 18.28

Pauling Negativity Number: 1.3

First Ionizing Energy (kJ/mol): (580)

Oxidation States: 4, 3


  • Emsley, John (2011). Nature's building blocks: An A-Z Guide to the Elements. Oxford University Press. ISBN 978-0-19-960563-7.
  • Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
  • Hammond, C. R. (2004). The Elements, in Handbook of Chemistry and Physics (81st ed.). CRC press. ISBN 978-0-8493-0485-9.
  • Seaborg, Glenn T.; James, R. A.; Ghiorso, A. (1949). "The New Element Curium (Atomic Number 96)." NNES PPR (National Nuclear Energy Series, Plutonium Project Record). The Transuranium Elements: Research Papers, Paper No. 22.2. 14 B. 
  • Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.