Fermium
Definition and meaning of Fermium in chemistry.
Fermium is a synthetic radioactive element with the symbol Fm and atomic number 100. It is a highly unstable member of the actinide series and holds the distinction of being the heaviest element that can be formed by macroscopic neutron bombardment of lighter elements.
In more detail
Fermium is a highly radioactive, artificially produced metal that does not occur naturally on Earth, having been entirely synthesized through nuclear reactions. Its chemical properties closely resemble those of other late actinides, typically exhibiting a +3 oxidation state in aqueous solutions, although a less stable +2 state can also be induced under strongly reducing conditions. Due to its exceptionally short half-life and the minuscule quantities in which it is produced, macroscopic amounts of pure fermium have never been isolated, making the direct measurement of its physical properties extremely difficult and largely theoretical. It is positioned in the f-block of the periodic table, right after einsteinium and before mendelevium. The element was first discovered in the radioactive fallout debris of the Ivy Mike nuclear test, which was the first successful detonation of a hydrogen bomb in 1952. Routine production for research purposes requires multiple successive neutron captures in a high-flux nuclear reactor, and its unstable isotopes generally decay by spontaneous fission or alpha decay shortly after their creation.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Fm |
| Atomic number | 100 |
| Atomic mass | [257] u |
| Category | Actinide |
| State at room temperature | Solid (presumed based on periodic trends) |
| Year discovered | 1952 in thermonuclear fallout |
| Discoverer | Albert Ghiorso and co-workers |
| Magnetic ordering | Unknown |
Fermium-257 is utilized in highly specialized scientific research to study the fundamental properties of heavy atomic nuclei and to provide the critical precursor material required to produce even heavier transuranic elements.
Frequently asked questions
Can fermium be found anywhere in natural environments?
No, fermium is completely synthetic and is only produced in high-flux nuclear reactors or particle accelerators, though trace amounts existed on Earth billions of years ago in natural nuclear fission reactors.
What is the most stable and longest-lived isotope of fermium?
Fermium-257 is the most stable known isotope, possessing a half-life of approximately 100.5 days before it decays via alpha emission or spontaneous fission.