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The Element Actinium

89

Ac

Actinium

227

Atomic Number: 89

Atomic Weight: 227

Melting Point: 1324 K (1051°C or 1924°F)

Boiling Point: 3471 K (3198°C or 5788°F)

Density: 10.07 grams per cubic centimeter

Phase at Room Temperature: Solid

Element Classification: Metal

Period Number: 7    Group Number: none    Group Name: Actinide

Radioactive

What's in a name? From the Greek word for a beam or ray, aktis.

Say what? Actinium is pronounced as ak-TIN-i-em.

History and Uses:

Actinium was discovered in 1899 by André-Louis Debierne, a French chemist, while experimenting with new methods of separating rare earth oxides. Friedrich Otto Giesel independently discovered actinium in 1902.

Actinium is a rare element that is present in uranium ores in tiny amounts, but it is usually cheaper and easier to create actinium when it is needed by bombarding radium with neutrons in a nuclear reactor.

Actinium's most stable isotope, actinium-227, has a half-life of 21.77 years. It decays into francium-223 through alpha decay or into thorium-227 through beta decay.

Actinium has no significant commercial applications, although it is used in the production of neutrons.

Estimated Crustal Abundance: 5.5×10-10 milligrams per kilogram

Estimated Oceanic Abundance: No Data Available

Number of Stable Isotopes: 0   (View all isotope data)

Ionization Energy: 5.17 eV

Oxidation State: +3

Electron Shell Configuration:

1s2
2s22p6
3s23p63d10
4s24p64d104f14
5s25p65d10
6s26p66d1
7s2