Chemical Properties
metal; hexagonal, a=0.3416 nm, c=1.1069 nm; in trivalent state, its properties are close to that of Ce+++; ionic radius of Bk+++ is 0.096nm, of Bk++++ is 0.0860 nm; enthalpy of vaporization 382kJ/mol; enthalpy of fusion 7.92 kJ/mol; first discovered in 1949 [KIR78] [KAT86] [MER06]
History
Berkelium [CAS: 7440-40-6], the atomic number is 97 and the chemical symbol is Bk. The name is derived from Berkeley, the town in California where the element was first synthesized in 1949 by the American scientific team Stanley G. Thompson, Albert Ghiorso, and Glenn T. Seaborg at the University of California, Berkeley, CA., using the nuclear reaction 241Am(4He, 2n) 243Bk. It is the eighth element in the Actinide series of the elements and was named in analogy with Terbium (for Ytterby the town in Sweden whose mine produced the ore), which is the eighth element in the Lanthanide series of the elements. The longest half-life associated with this unstable element is 1400 year 247Bk. See also Berkelium.
