Californium Californium 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 (then the University of California Radiation Laboratory), by bombarding curium with alpha particles (helium-4 ions). It is an actinide element, the sixth transuranium element to be synthesized, and has the second-highest atomic mass of all the elements that have been produced in amounts large enough to see with the unaided eye (after einsteinium). The element was named after the university and the state of California. Two crystalline forms exist for californium under normal
Californium made by bombarding berkelium-249 () with neutrons, forming berkelium-250 () via neutron capture (n,γ) which, in turn, quickly beta decays (β) to californium-250 () in the following reaction: Bombardment of californium-250 with neutrons produces californium-251 and californium-252. Prolonged irradiation of americium, curium, and plutonium with neutrons produces milligram amounts of californium-252 and microgram amounts of californium-249. As of 2006, curium isotopes 244 to 248 are irradiated by neutrons in special reactors to produce primarily californium-252 with lesser amounts of isotopes 249 to 255. Microgram quantities of californium-252 are available for commercial use through the U.S. Nuclear Regulatory Commission. Only two