Californium Facts

Chemical & Physical Properties of Californium

This is a button of pure californium, about 1 mm in diameter.
Californium is a man-made radioactive metal. This is a button of pure californium, about 1 mm in diameter. Richard G. Haire, US DOE

Californium Basic Facts

Atomic Number: 98
Symbol: Cf
Atomic Weight: 251.0796
Discovery: G.T. Seaborg, S.G. Tompson, A. Ghiorso, K. Street Jr. 1950 (United States)
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.

Electron Configuration

[Rn] 7s2 5f10

Californium Physical Data

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

References: Los Alamos National Laboratory (2001), Crescent Chemical Company (2001), Lange's Handbook of Chemistry (1952), CRC Handbook of Chemistry & Physics (18th Ed.)

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Helmenstine, Anne Marie, Ph.D. "Californium Facts." ThoughtCo, Mar. 9, 2017, Helmenstine, Anne Marie, Ph.D. (2017, March 9). Californium Facts. Retrieved from Helmenstine, Anne Marie, Ph.D. "Californium Facts." ThoughtCo. (accessed November 18, 2017).