7440-34-8[Ac]QQINRWTZWGJFDB-UHFFFAOYSA-NActinium atom is an actinoid atom, a scandium group element atom and a f-block element atom.
7440-34-8DTXSID10225388CHEBI:33337Silvery metal; cubic crystal; melts at 1,051°C; vaporizes at 3,198°C; density 10.0 g/cm3
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Of all Actinium radionuclides, Actinium-227 (14952-40-0) has the longest half life at 21.77 years. Mode of decay is alpha, beta, and gamma emission. Ac-228 has a half life of 6 hours and decays by beta and gamma emission. [Merck Index # 137] Internal toxicity is Very High for Ac-227 (ALI = 0.004 mCi) and Ac-225 (ALI = 0.005 mCi) and High for Ac-228 (ALI = 0.02 mCi); Lung clearance half-time is >100 days for oxides and hydroxides, 10-100 days for halides and nitrates, and <10 days for other compounds. [NRC ALIs] The specific gamma ray constant for Ac-227 = ~2.2 [Gusev, p. 587] See Radiation, ionizing.
All nuclides (Ac-209 through Ac-233) are radioactive. Ac-227 occurs naturally in the decay series of U-235. It is also produced by neutron bombardment of Ra-226. Ac-228 occurs naturally in the decay series of Th-232. [Merck Index # 137] Ac-225 (alpha decay/10 day half-life) and Ac 227 (alpha decay/21.8 years) are attached to monoclonal antibodies to treat cancer; [Waltar, p. 277] With a half-life of 10 days and 4 alpha particles in the decay chain, Ac-225 is ideal for radioimmunotherapy. However, this therapy is limited by the radiotoxicity of the daughter radionuclides. There is limited commercial use of actinium. Exposure may occur in research scientists. [HSDB]
개요Actinium-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.
출처Actinium-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.
역사The 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.
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