Actinium

Description

A naturally occurring, radioactive element found in uranium ores. Actinium has a half-life of 21.77 years. Metallic actinium is silvery white and produces a faint blue glow which is visible in the dark. Actinium was first isolated and named in 1899 by André Debierne; in 1902, it was independently discovered by Friedrich Giesel and named emanium. The two elements were reconciled as one in 1904. Actinium is a highly reactive material with a strong basic character that produces water-insoluble salts with most anions. It is very difficult to extract and separate from uranium ores and has limited commercial applications.

Synonyms and Related Terms

Ac; emanium; aktinium (Ces., Sven.); Actinium (Dan., Deut., Fr., Ned., Nor.); actinio (Esp.); attinio (It.); (Ned.); aktyn (Pol.); actínio (Port.)

Other Properties

Reacts with water to produce hydrogen gas.

Composition	Ac (atomic no. 89)
CAS	7440-34-8
Melting Point	1050
Density	10.07
Molecular Weight	atomic wt=227
Boiling Point	about 3300

Hazards and Safety

Extremely hazardous. Radioactive bone-seeking poison.

Sources Checked for Data in Record

• G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 649

• Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993

• The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983

• The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998

• Chemical & Engineering News, American Chemical Society, Washington DC, 81 (36) , Sept. 8, 2003 Comment: "Actinium" by Greg Wall, p. 162