Fermium, a synthetic element with the atomic number 100, is a highly radioactive element that exists only fleetingly in specialized laboratories. Its name is a tribute to a giant of modern physics whose achievements made the creation of such heavy elements possible. Understanding why this element received such an honor requires looking back at the scientific legacy that shaped the nuclear age.
Honoring Enrico Fermi
Fermium was named in honor of the Italian-American physicist Enrico Fermi (1901–1954), a Nobel laureate recognized as one of the most influential scientists of the 20th century. Fermi’s foundational work focused on the behavior of neutrons, essential for creating elements like Fermium. He won the 1938 Nobel Prize in Physics for demonstrating the existence of new radioactive elements produced by neutron irradiation.
His most famous achievement was supervising the construction and operation of the world’s first controlled nuclear reactor during the Manhattan Project. This device, Chicago Pile-1, achieved the first self-sustaining nuclear chain reaction on December 2, 1942. Fermi’s ability to excel in both theoretical physics and experimental physics earned him the title of the “architect of the nuclear age.”
The element was officially named Fermium in 1955, shortly after his death, acknowledging his pioneering contributions to nuclear science. The discovery of new transuranic elements fundamentally relied on the techniques of neutron bombardment and understanding nuclear chain reactions that Fermi had established.
The Context of Discovery
The physical creation and initial identification of element 100 occurred in an unusual setting: the radioactive debris of a thermonuclear explosion. Fermium was first detected in the fallout collected after the “Ivy Mike” test, the first full-scale test of a hydrogen bomb, detonated in the Pacific on November 1, 1952. The immense and instantaneous neutron flux produced by the explosion was unlike anything achievable in a laboratory reactor at the time.
This powerful burst of energy allowed uranium atoms in the device’s casing to undergo rapid, multiple neutron capture. The uranium-238 nuclei absorbed up to 17 neutrons before undergoing successive beta decays. This process resulted in the formation of extremely heavy, neutron-rich isotopes, including those of element 99 (Einsteinium) and element 100.
A team led by Albert Ghiorso at the University of California, Berkeley, isolated and identified the elements by studying contaminated coral and filter papers from the blast site. The discovery demonstrated a new mechanism for synthesizing super-heavy elements. However, it was kept highly classified by the U.S. military until 1955 due to its connection to nuclear weapons research.
Characteristics of Element 100
Fermium is a synthetic transuranic element and is classified as an actinide. It does not occur naturally on Earth. All isotopes of Fermium are highly radioactive and unstable, decaying quickly.
The most stable isotope is Fermium-257, which has a half-life of approximately 100.5 days. Due to its short lifespan and difficulty of production, the element is only ever produced in extremely minute, tracer quantities. It is the heaviest element that can be produced through intense neutron bombardment in a high-flux nuclear reactor.
Fermium has no industrial or commercial applications due to its scarcity and rapid decay rate. Its only purpose is for scientific research, where it is used to study the chemical properties of the heaviest atoms and to push the boundaries of nuclear physics.