Americium: the essentials

The lustre of freshly prepared americium metal is whiter and more silvery than plutonium or neptunium prepared in the same manner. Americium is a component of the smoke detector above.

Americium appears to be more malleable than uranium or neptunium and americium tarnishes slowly in dry air at room temperature. Americium is a radioactive rare earth metal which must be handled with care to avoid contact, since it is a heavy α and γ emitter. It is named after America. The α activity of 241Am is about three times that of radium. Americium is available to qualified users in the UK and in the USA.

Americium is a key component of some smoke detectors.

Americium: historical information

Americium was discovered by Glenn Seaborg, Ralph James., L. Morgan, Albert Ghiorso in 1944 at USA. Origin of name: from the English word "America".

Americium was was identified by Seaborg and others in 1944 as the result of successive neutron capture reactions by plutonium isotopes in a nuclear reactor.

Americium around us Read more »

Americium has no biological role.

Americium is radioactive but is not present in the geosphere in any significant quantity.

Abundances for americium in a number of different environments. More abundance data »
Location ppb by weight ppb by atoms Links
Universe (no data) (no data) Chemical elements abundance by weight in the universe on a miniature periodic table spark table
Crustal rocks (no data) (no data) Chemical elements abundance by weight in the earth's crust on a miniature periodic table spark table
Human (no data) ppb by weight (no data) atoms relative to C = 1000000 Chemical elements abundance by weight in humans on a miniature periodic table spark table

Physical properties Read more »

Heat properties Read more »

Crystal structure Read more »

The solid state structure of americium is: hcp (hexagonal close-packed).

Americium: orbital properties Read more »

Americium atoms have 95 electrons and the shell structure is The ground state electronic configuration of neutral Americium is [Rn].5f7.7s2 and the term symbol of Americium is 8S7/2.


Isolation: coming soon!

Americium isotopes Read more »

Table. Stables isotopes of americium.
Isotope Mass
(atom %)
spin (I)
moment (μ/μN)

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