Berkelium
Symbol: Bk
Atomic Number: 97
Atomic Mass: 247.0 amu (atomic mass units)
Melting Point: 1050 C (1323 K, 1922 F)
Boiling Point: Unknown
Number of Protons: 97
Number of Electrons: 97
Number of Neutrons: 150
Classification: Rare Earth Metal (Man Made)
Crystal Structure: Unknown
Density @ 293 K: 14 grams per cubic centimeter
Color: Unknown
Berkelium is a radioactive, man made, rare earth element of the actinide or actinoid series. It was first produced in December 1949 by the team of Stanley G. Thompson, Glenn T. Seaborg, Kenneth Street, Jr. and Albert Ghiorso. At the time the scientists were working at the University of California campus in Berkeley, California and it is from that city the element gets its name. To produce this new element the scientists bombarded microgram amounts of the isotope americium-241 with alpha particles using a cyclotron. With each atom of the isotope berkelium-243 that was produced two free neutrons were released.
In 1962 the first compound of berkelium was reported when researchers produced three billionths of a gram of berkelium chloride. Since then the compounds berkelium oxychloride, berkelium dioxide, berkelium trioxide and berkelium fluoride have all been produced. These compounds were identified and studied using the X-ray diffraction methodology.
Only a very small amount of the element has been produced and some of its bulk properties such as its boiling point are not known. Although an insufficient amount have been made to ascertain its appearance knowledge of other rare earth elements suggest it would be metallic and white, silver or gray in color.
Twenty three isotopes of berkelium have been produced to date. All of the known isotopes of berkelium are unstable. The isotope with the longest half life is berkelium-247 at approximately 1380 years. Berkelium-247 decays by alpha decay to form americium-243. The isotope with the shortest half life is berkelium-242m at 9.5 nanoseconds, this isotope decays by spontaneous fission.
It is highly unlikely that berkelium will ever have any industrial uses. The small amount of the element that can be produced using current methods means that it only has uses in scientific research. It is reported that the isotope berkelium-249 has been used to produce some new isotopes of the super-heavy element bohrium at the Paul Scherrer Institute Laboratories in Switzerland.
There is evidence that the element tends to accumulate in the skeleton so given its radioactive nature researchers have to take extreme care when working with berkelium.
