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The Periodic Table

118 elements, raised by their properties.

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About Californium

Californium is a synthetic chemical element; it has symbol Cf and atomic number 98. It was first synthesized in 1950 at Lawrence Berkeley National Laboratory (then the University of California Radiation Laboratory) by bombarding curium with alpha particles (helium-4 ions). It is an actinide element, the sixth transuranium element to be synthesized, and has the second-highest atomic mass of all elements that have been produced in amounts large enough to see with the naked eye (after einsteinium). It was named after the university and the U.S. state of California.

Two crystalline forms exist at normal pressure: one above and one below 900 °C (1,650 °F). A third form exists at high pressure. Californium slowly tarnishes in air at room temperature. Californium compounds are dominated by the +3 oxidation state. The most stable of californium's twenty known isotopes is californium-251, with a half-life of 898 years. This short half-life means the element is not found in significant quantities in the Earth's crust. 252Cf, with a half-life of about 2.645 years, is the most common isotope used and is produced at Oak Ridge National Laboratory (ORNL) in the United States and Research Institute of Atomic Reactors in Russia.

The text above is from the lead of the Wikipedia article “Californium” (retrieved 2026-11-05), used under CC BY-SA 4.0. Read on Wikipedia · CC BY-SA 4.0

Data and notes

Column height is a linear display mapping; the shortest column is not zero. Data: PubChem, IAEA.

Solid columns are measured, frosted glass is predicted, empty frames have no value.

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