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californium cal·i·for·ni·um (kāl'ə-fôr'nē-əm)
A synthetic radioactive element produced in trace quantities by neutron bombardment of curium. Its most stable isotope, Cf 251, has a half-life of 790 years. Atomic number 98.
A synthetic, radioactive metallic element of the actinide series that is produced from curium or berkelium and is used in chemical analyses. Its most stable isotope, Cf 251, has a half-life of 800 years. Atomic number 98. See Periodic Table.
synthetic chemical element of the actinoid series of the periodic table, atomic number 98. Not occurring in nature, californium (as the isotope californium-245) was discovered (1950) by Stanley G. Thompson, Kenneth Street, Jr., Albert Ghiorso, and Glenn T. Seaborg at the University of California, Berkeley, as a product resulting from the helium-ion bombardment of curium-242 (atomic number 96) in the 60-inch cyclotron.