Berkelium

Shells	2,8,18,32,26,9,2	Electron configuration	[Rn] 5f9 7s2
Minimum oxidation number	0	Maximum oxidation number	4
Minimum common oxidation number	0	Maximum common oxidation number	3

Number of isotopes		0	Hydride(s)
Oxide(s)		BkO Bk2O3 BkO2	Chloride(s)		BkCl3

Thermal conductivity		J/m-sec-deg	Electrical conductivity		1/mohm-cm
Polarizability		22.7 A^3

(Berkeley, home of the University of California) Berkelium, the eighth member of the actinide transition series, was discovered in December 1949 by Thompson, Ghiorso, and Seaborg, and was the fifth transuranium element synthesized. It was produced by cyclotron bombardment of milligram amounts of 241Am with helium ions at Berkeley, California. The first isotope produced had a mass of 243 and decayed with a half-life of 4.5 hours. Ten isotopes are now known and have been synthesized. The evidence of 249Bk with a half-life of 314 days, makes it feasible to isolate berkelium in weighable amounts so that its properties can be investigated with macroscopic quantities. One of the first visible amounts of a pur berkelium compound, berkelium chloride, was produced in 1962. It weighed 1 billionth of a gram. Berkelium probably has not yet been prepared in elemental form, but is expected to be a silvery metal, easily soluble in dilute mineral acids, and readily oxidized by air or oxygen at elevated temperatures to form the oxide. X-ray diffraction methods have been used to identify various compounds. As with other actinide elements, berkelium tends to accumulate in the skeletal system. Because of its rarity, berkelium presently has NO COMMERCIAL OR TECHNOLOGICAL USE.