Californium: Radioactive Man-made Element Number 98

Californium, discovered February 9th, 1950, University of California

Fun Facts About Californium

Scientists at the University of California, Berkeley laboratories synthesized the first atoms of the element californium. It was created by bombarding a curium target with high energy alpha particles.

Atomic Number: 98

Symbol: Cf

Atomic Weight: 251.0796

Discovery: G.T. Seaborg, S.G. Tompson, A. Ghiorso, K. Street Jr. 1950 (United States)

Electron Configuration: [Rn] 7s² 5f¹⁰

Word Origin: State and University of California

Properties: Californium metal has not been produced. Californium (III) is the only ion stable in aqueous solutions. Attempts to reduce or oxidize californium (III) have been unsuccessful. Californium-252 is a very strong neutron emitter.

Uses: Californium is an efficient neutron source. It is used in neutron moisture gauges and as a portable neutron source for metal detection.

Isotopes: The isotope Cf-249 results from the beta decay of Bk-249. Heavier isotopes of californium are produced by intense neutron irradiation by the reactions. Cf-249, Cf-250, Cf-251, and Cf-252 have been isolated.

Sources: Californium was first produced in 1950 by bombarding Cm-242 with 35 MeV helium ions.

Element Classification: Radioactive Rare Earth (Actinide)

Density (g/cc): 15.1

Melting Point (K): 900

Atomic Radius (pm): 295

Pauling Negativity Number: 1.3

First Ionizing Energy (kJ/mol): (610)

Oxidation States: 4, 3

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