Discovery date : 1950
Discovered by: Stanley Thompson, Kenneth Street, Jr., Albert Ghiorso, and Glenn Seaborg
Origin of the name: Californium is named for the university
and state of California, where the element was first made.
Allotropes :
~>CALIFORNIUM is a radioactive chemical element with symbol Cf and atomic number 98. The element was first synthesized in 1950 at the Lawrence Berkeley National Laboratory, by bombarding curium with alpha particles.
| FACT BOX | |||
| Group | Actinides | Melting point | 900°C, 1652°F, 1173 K |
| Period | 7 | Boiling point | Unknown |
| Block | f | Density (g cm−3) | 15.1 |
| Atomic number | 98 | Relative atomic mass | [251] |
| State at 20°C | Solid | Key isotopes | 249Cf,252Cf |
| Electron configuration | [Rn] 5f107s2 | CAS number | 7440-71-3 |
| ChemSpider ID | 22433 | ChemSpider is a free chemical structure database | |
Californium was first made in 1950 at Berkeley, California, by a team consisting of Stanley Thompson, Kenneth Street Jr., Albert Ghiorso, and Glenn Seaborg. They made it by firing helium nuclei (alpha particles) at curium-242. The process yielded the isotope californium-245 which has a half-life of 44 minutes. Curium is intensely radioactive and it had taken the team three years to collect the few milligrams needed for the experiment, and even so only a few micrograms of this were used. Their endeavours produced around 5,000 atoms of californium, but there was enough to show it really was a new element.