What is Curium?
Curium (symbol Cm) is element 96 on the periodic table, a actinide in period 7. Named for the Curies, and the isotope that has analysed the soil of Mars. At room temperature it is a solid, and it is radioactive.
The story
What curium is, and how we found it
Named for the Curies, and the isotope that has analysed the soil of Mars.
The discovery of curium
Summer Discovery - 1944
Glenn T. Seaborg, Ralph A. James, and Albert Ghiorso discovered curium at the University of California, Berkeley, in the summer of 1944. This discovery came just months after their discovery of americium, marking an incredibly productive period in transuranium element research.
The Breakthrough Experiment
Alpha Particle Bombardment: The team created curium by bombarding plutonium-239 with alpha particles (helium-4 nuclei) in Berkeley"s 60-inch cyclotron. This high-energy collision produced curium-242, which they detected through its characteristic alpha decay pattern.
Chemical Identification: The most challenging aspect was chemically separating and identifying element 96 from the plutonium target and other reaction products. Seaborg"s innovative chemical techniques proved that this new element had properties consistent with being the sixth member of the actinide series.
Scientific Achievement
Actinide Theory Confirmation: Curium"s discovery provided crucial evidence for Seaborg"s significant actinide theory, which predicted that elements 89-103 would form a separate series analogous to the lanthanides. This insight reorganized our understanding of the entire periodic table.
Nuclear Physics Advance: The discovery demonstrated that scientists could systematically create new elements heavier than uranium, opening the door to the entire field of superheavy element research.
Honoring Scientific Giants
Marie and Pierre Curie: The discoverers named element 96 "curium" to honor Marie and Pierre Curie, the pioneering researchers who discovered radium and polonium and established the foundations of nuclear chemistry. This was the first element named after scientists (rather than places or mythological figures).
Fitting Tribute: The choice was particularly appropriate because the Curies" work with radioactive elements directly enabled the discovery of curium and all subsequent transuranium elements.
Wartime Classification
Secret Research: Like other wartime nuclear discoveries, curium"s existence was kept classified until after World War II ended. The discovery was publicly announced in 1945, along with americium and other transuranium elements.
Manhattan Project Context: While curium had no immediate weapons applications, its discovery advanced fundamental understanding of nuclear reactions and heavy element chemistry that supported the broader nuclear weapons program.
Nobel Prize Achievement
Recognition: Glenn Seaborg"s discovery of curium and other transuranium elements earned him the Nobel Prize in Chemistry in 1951, shared with Edwin McMillan. Their work established the modern understanding of superheavy elements.
Scientific Legacy: The techniques developed for curium"s discovery became the foundation for synthesizing all subsequently discovered transuranium elements, making it a cornerstone achievement in nuclear chemistry.