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.