Californium

Chemical, physical and material properties and data of the chemical element Californium.

Contents

General data

Atomar properties

Electron configutation

Californium, a late actinide with twenty known isotopes, is a man-made transuranium chemical element that does not occur naturally. It was first identified by Glenn Seaborg and his co-workers in February 1950 in an experiment that used a 60-inch cyclotron to bombard curium isotope Cm²⁴² with helium ions:

24296Cm + 42He → 24598Cf + 10n.

Although primarily named for the state of California, it also honors the University of California at Berkeley where many elements were first discovered.

General Information about Californium

Regular nameCaliforniumChemical symbolCfOther namesElement 98Historical namesAccretium, Cyclonium, Cyclotronium, Enactinium, Enneactinium, Euprosium, Lewisium, Nonactinium, Praedicium, Radlabium (all rejected proposals)Name meaning, originCalifornia (US state, location of the research facility)Discovery (year)(1950) - California Radiation Laboratory, Berkeley (Stanley Gerald Thompson, Kenneth Street Jr., Albert Ghiorso, Glenn T. Seaborg)OccurenceOnly artificially producible chemical element.Position in the PSEPeriod 7, f-block, actinoidsGroup membershipTransuranium element

Atomar Properties of Californium

Atomic number Z98 = number of protonsStandard Atomic Weight251.079589428

Electron configuration of Californium

1s	2s	2p	3s	3p	3d	4s	4p	4d	4f	5s	5p	5d	5f	6s	6p	6d	6f	7s	7p
2	2	6	2	6	10	2	6	10	14	2	6	10	10	2	6			2

Shorthand electron configuration of Californium: [Rn] 5f¹⁰ 7s² .

Ionization Energies of Californium

The following table lists the ionization energies IE (ionization potentials); the IE is the energy required in electron volt (eV) per atom to separate a given electron from an Californium atom.

IE1	IE2
6.2817	11.8

Isotopic Data of Californium

An overview of the nuclides as well as the isotopic data and properties are listed on the following page: Californium isotopes.

Chemistry of Californium

Oxidation states+II. +III. +IV. +VElectronegativity1.3 (Pauling original)
1.30 (Pauling)Electron affinity-1.01 eV
-97.31 kJ mol^-1

Material and Physical Properties

The following table lists some calculated or experimentally determined physical data or material properties of californium.

Melting point900 °CBoiling point1470 °CDensity15.1 g cm^-3

Use of Californium

The element has a certain practical importance in the form of the isotope californium-252, which is used in various areas as a neutron source.

External Data, Identifiers

CAS registry number7440-71-3InChI =1S/CfInChIKeyHGLDOAKPQXAFKI-UHFFFAOYSA-NPubChem ID23997

Literature Sources and References

[1] - S. G. Thomson:
New element californium (atomic number 98).
In: OSTI Technical Report, (1950), DOI https://www.osti.gov/biblio/381639.

[2] - Thomas Albrecht-Schmitt:
Californium gleaming.
In: Nature Chemistry, (2014), DOI 10.1038/nchem.2035.

[3] - Samantha K. Cary, Monica Vasiliu, Ryan E. Baumbach et al.:
Emergence of californium as the second transitional element in the actinide series.
In: Nature Communications, (2015), DOI 10.1038/ncomms7827.

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Last update: 2022-12-05

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