| Questions and Answers (Q&A) | Back Directory | [Chemical Properties]
Silvery metal; cubic crystal; melts at 1,051°C; vaporizes at 3,198°C; density 10.0 g/cm3
| [Reactions]
Actinium behaves like lanthanum forming mostly the trivalent salts of the metal. It is strongly electropositive, the first ionization potential being 5.17eV. Reacts with HCl forming AcCl3; also reacts with organic acids forming corresponding salts; combustion in air can produce oxide and nitride; susceptible to react with CO2 forming carbonate.
| [Hazard]
Toxicity: Exposure to radiation can cause cancer.
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| Hazard Information | Back Directory | [Description]
Actinium-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. | [Physical properties]
Silvery metal; cubic crystal; melts at 1,051°C; vaporizes at 3,198°C; density 10.0 g/cm3. | [Occurrence]
Actinium-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.
| [History]
The 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. | [Definition]
ChEBI: Actinium atom is a scandium group element atom, an actinoid atom and a f-block element atom. |
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