Discovered | Name | Characteristics | Uses

Californium is a member of the actinide series, which stretches from actinium (Ac) to lawrencium (Lr). Californium is a synthetic element; none occurs naturally on earth.

The element was first prepared in 1950 by a group headed by Stanley Thompson (and including K. Street, Jr., A. Ghioroso, and G. Seaborg). It was prepared by bombarding a curium target with alpha particles.

242Cm + 4He 1n + 245Cf

The name of the element comes from the fact that it was discovered at the University of California in Berkeley, California.

Only a few thousand atoms of the element were originally isolated. However, tracer experiments have indicated possible oxidation states of +2, +3, +4, with +3 the most stable. Subsequently, the compounds Cf2O3, CfF3, and CfOCl have been identified.

Like americium and curium, Cm has been used as a neutron source for neutron activation analysis, which can detect trace quantities of many elements.

At least 16 isotopes of Cf are known, ranging from mass numbers of 240 to 255. The most stable isotope is 251Cf, which has a half-life of about 890 years.