|Boiling Point: unknown
Melting Point: 1259°K, 986°C, 1807°F
Elec. Energy Level: 2, 8, 18, 32, 26, 9, 2
Isotopes: 20 + None Stable + 1 Meta State
Heat of Vaporization: unknown
Heat of Fusion: unknown
Density: 14.78 g/cm3 @ 300oK (Est.)
Specific Gravity: 14 (est.)
Atomic Radius: unknown
Ionic Radius: 0.949Å
Electronegativity: 1.3 (Pauling), 1.2 (Allrod Rochow)
1s2 2s2p6 3s2p6d10 4s2p6d10f14 5s2p6d10f8 6s2p6d1 7s2
(Berkeley, home of the University of California) Berkelium, the eighth member of the actinide transition series was the fifth transuranium element synthesized. Berkelium was first synthesized by Glenn T. Seaborg, Albert Ghiorso, Stanley G. Thompson, and Kenneth Street, Jr at the University of California, Berkeley in December 1949. The team used a cyclotron to bombard a milligram-sized target of 241Am with alpha particles to produce 243Bk (half-life 4.5 hours) and two free neutrons. One of the longest lived isotopes of the element, 249Bk (half-life 330 days), was later synthesized by subjecting a 244Cm target with an intense beam of neutrons.
Weighable amounts of 249Bk (half-life 314 days) make it possible to determine some of its properties using macroscopic quantities. The first visible amounts of a berkelium compound, berkelium chloride (BkCl3) was produced in 1962 and weighed about 3 billionths of a gram (0.000000003 grams). Berkelium oxychloride (BkOCl), berkelium fluoride (BkF3), berkelium dioxide (BkO2) and berkelium trioxide (BkO3) have been identified and studied with a method known as X-ray diffraction. As with other actinide elements, berkelium tends to accumulate in the skeletal system. The maximum permissible body burden of 249Bk in the human skeleton is about 0.0004 ug. Because of its rarity, berkelium presently has no known uses outside of basic research and plays no biological role. As of 2004 it had not been isolated in its elemental form, but it is predicted to be a silvery metal that would easily oxidize in air at elevated temperatures and would be soluble in dilute mineral acids. Berkelium-249 is available from O.R.N.L. at a cost of $160/ug plus packing charges.
As of 2004, it had not been isolated in its elemental form, but it is predicted to be a silvery metal that would easily oxidize in air at elevated temperatures and would be soluble in dilute mineral acids.
|Berkelium Oxychloride, BkOCl|
|Berkelium Fluoride, BkF3||Berkelium Dioxide, BkO2|
|Berkelium Trioxide, BkO3||Berkelium Chloride, BkCl3|
19 radioisotopes of berkelium have been characterized, with the most stable being 247Bk with a half-life of 1380 years, 248Bk with a half-life of >9 years, and 249Bk with a half-life of 330 days. All of the remaining radioactive isotopes have half-lives that are less than 5 days, and the majority of these have half-lives that are less than 5 hours. This element also has 2 meta states, with the most stable being 248mBk (t½ 23.7 hours). The isotopes of berkelium range in atomic weight from 235.057 amu (235Bk) to 254.091 amu (254Bk).
|247Bk||247.070307||1.38 x 103 y|
Like other actinides, berkelium bio-accumulates in skeletal tissue. This element has no known uses outside of basic research and plays no biological role.
Atomic Radius (Å): unknown
Electrochemical Equivalents: 3.0727 g/amp-hr
Atomic Mass Average: 247