Actinium

DescriptionActinium-227 occurs in uranium ore and is a decay product of uranium-235. It is found in equilibrium with its decay products. It is prepared by bombarding radium atoms with neutrons. Chemically, the metal is produced by reducing actinium fluoride with lithium vapor at 1,100℃ to 1,300℃. AcF3+Li→Ac + 3LiF The element was discovered independently by A. Debierne and F. Giesel in 1899 and 1902, respectively. It is used in nuclear reactors as a source of neutrons.

OccurrenceActinium-227 occurs in uranium ore and is a decay product of uranium-235. It is found in equilibrium with its decay products. It is prepared by bombarding radium atoms with neutrons. Chemically, the metal is produced by reducing actinium fluoride with lithium vapor at 1,100°C to 1,300°C. AcF3+Li→Ac + 3LiF The element was discovered independently by A. Debierne and F. Giesel in 1899 and 1902, respectively. It is used in nuclear reactors as a source of neutrons.

HistoryThe name Actinium derives from the Greek, aktis or akinis for “beam or ray” because in equilibrium with its decay products, actinium is a powerful source of alpha radiation. The discovery has been credited to the French chemist Andre-Louis Debierne in 1899. It was independently discovered by German chemist Friedrich Oskar Giesel in 1902, who called it emanium. It is thought that Debierne’s original preparation actually consisted of two thorium isotopes, 227Th and 230Th, but there was confusion in those early discoveries in radioactivity and Debierne’s claim prevailed and his name of actinium has been retained to this day. The longest half-life associated with this unstable element is 21.77 year 227Ac.