- californium
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/kal'euh fawr"nee euhm/, n. Chem.a transuranic element. Symbol: Cf; at. no.: 98.[1945-50; named after the University of CALIFORNIA where it was discovered; see -IUM]
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(Cf),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.All californium isotopes are radioactive; the long-lived isotopes are produced from berkelium-249 or from californium-249. They are: californium-249 (360-year half-life); californium-250 (13-year half-life); californium-251 (800-year half-life); and californium-252 (2.65-year half-life). These isotopes have been used in tracer amounts for investigating the chemistry of californium (which exhibits an oxidation state of +3 in acidic aqueous solution) and for preparing microgram quantities of compounds such as the oxychloride CfOCl, the oxide Cf2O3, and the trichloride CfCl3. There is some evidence for a +2 state also. Metallic californium has not yet been prepared.Californium-252, because 3 percent of its decay occurs by spontaneous fission, is industrially and medically important as a very intense point source of neutrons. One microgram releases 170,000,000 neutrons per minute.atomic number98stablest isotope251oxidation state+3electronic config.[Rn]5f 107s2* * *
Universalium. 2010.
