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The Element Californium

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98

Cf

Californium

251

Atomic Number: 98

Atomic Weight: 251

Melting Point: 1173 K (900°C or 1652°F)

Boiling Point: Unknown

Density: Unknown

Phase at Room Temperature: Solid

Element Classification: Metal

Period Number: 7    Group Number: none    Group Name: Actinide

Radioactive and Artificially Produced

What's in a name? Named for the state and University of California.

Say what? Californium is pronounced as kal-eh-FOR-nee-em.

History and Uses:

Californium was first produced by Stanley G. Thompson, Glenn T. Seaborg, Kenneth Street, Jr. and Albert Ghiorso working at the University of California, Berkeley, in 1950. They bombarded atoms of curium-242 with helium ions using a device known as a cyclotron. This produced atoms of californium-245, an isotope with a half-life of about 45 minutes, and a free neutron.

Californium-252, an isotope with a half-life of about 2.6 years, is a very strong neutron source. One microgram (0.000001 grams) of californium-252 produces 170,000,000 neutrons per minute. It is being used as a neutron source to identify gold and silver ores through a technique known as neutron activation. It is also being used in devices known as neutron moisture gauges that are used to find water and oil bearing layers in oil wells.

A few compounds of californium have been produced and studied. They include: californium oxide (CfO3), californium trichloride (CfCl3) and californium oxychloride (CfOCl).

Californium's most stable isotope, californium-251, has a half-life of about 898 years. It decays into curium-247 through alpha decay or decays through spontaneous fission.

Estimated Crustal Abundance: Not Applicable

Estimated Oceanic Abundance: Not Applicable

Number of Stable Isotopes: 0   (View all isotope data)

Ionization Energy: 6.30 eV

Oxidation States: +3

Electron Shell Configuration:

1s2

2s2   2p6

3s2   3p6   3d10

4s2   4p6   4d10   4f14

5s2   5p6   5d10   5f10

6s2   6p6

7s2