Periodic TableAll elementsCalifornium
No. 098
Cf
251 u
Element · Actinide

Californium

Californium (锎, symbol Cf) is chemical element number 98, an Actinide in period 7 of the periodic table, with a standard atomic weight of about 251. Powerful neutron emitter. Used to start nuclear reactors and in cancer therapy.

Period 7Group —[Rn] 5f¹⁰ 7s²

Properties

Atomic number98
SymbolCf
Atomic mass251 u
CategoryActinide
Period7
Group
Electron configuration[Rn] 5f¹⁰ 7s²
Electronegativity1.3
Covalent radius
Density15.1 g/cm³
Melting point1173 K
Boiling point1743 K
DiscoveryThompson, Street, Ghiorso, Seaborg, 1950

Overview

Powerful neutron emitter. Used to start nuclear reactors and in cancer therapy. Californium (Cf) is an Actinide with atomic number 98, located in period 7. As an actinide it is typically radioactive and closely tied to nuclear technology.

Its electron configuration is [Rn] 5f¹⁰ 7s², with 2 electrons in the outer shell, and an electronegativity of about 1.3 (Pauling). Around 25 °C it is usually a solid; it melts near 1173 K (899.9 °C), boils near 1743 K (1469.9 °C), has a density around 15.1 g/cm³.

In industry and daily life it turns up in Research and Nuclear. It is regarded as a high-hazard element, so handle it with appropriate care. It was first described by Thompson, Street, Ghiorso, Seaborg in 1950. Use the comparison tool to line it up against other elements.

Electron shells

Cf98

Electrons per shell: 2 · 8 · 18 · 32 · 28 · 8 · 2

Main uses

Hazard

HighRadioactive

Compounds containing Californium

No compounds in this knowledge base contain Californium yet.

Data sources

Atomic mass uses IUPAC (CIAAW) standard atomic weights; the covalent radius is from Cordero et al. (2008). Verify on the RSC Periodic Table, PubChem and Wikipedia. Educational reference only.