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Author: langbot
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English[en]
Californium is a radioactive chemical element with the symbol Cf and atomic number 98. The element 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). The element was named after the university and the U.S. state of California. Two crystalline forms exist for californium 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.[a] 252Cf, with a half-life of about 2.645 years, is the most common isotope used and is produced at Oak Ridge National Laboratory in the United States and Research Institute of Atomic Reactors in Russia.
Cornish[kw]
Elven gymyk yw kaliforniom, niver 98 y'n Vosen Beriodek. Y furvell gymyk yw Cf. An hanow a dheu dhyworth Kaliforni, yn le may veu gwrys war an prys kynsa. Usys yw dhe hwilas moon hag yn diagnosans medhegel. Peryllus yw drefen y vos pennfenten glew a dhewynnyans, hag ev a dhyllo nywtrons. Usys yw an nywtrons dhe ladha kankres. Gwrys veu yn kynsa yn Pennskol Kaliforni yn mis Hwevrer 1950 gans bagas ow komprehendya Stanley Thompson, Kenneth Street, Albert Ghiorso ha Glenn Seaborg. Askorrys yw kaliforniom yn dasoberoryon nuklerek. Ny gevys yn naturel war an Norvys. Y boos atomek yw 252.1. Ny wodhvedhys pyth yw y boyntow teudhi ha bryjyon.