Californium is a synthetic radioactive metallic chemical element in the actinide series with the symbol Cf and atomic number 98. Californium was first synthesized at the University of California, Berkeley by the physics researchers Stanley G. Thompson, Kenneth Street, Jr., Albert Ghiorso, and Glenn T. Seaborg on or about February 9, 1950. It was the sixth transuranium element to be discovered; the team announced its discovery on March 17, 1950. Read more