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 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.
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Physical properties Read more »
- Density of solid: 13780 kg m-3
- Molar volume: 17.63 cm3
- Thermal conductivity: 10 (estimate) W m‑1 K‑1
Heat properties Read more »
- Melting point: 1449 [1176 °C (2149 °F)] K
- Boiling point: 2880 [2607 °C (4725 °F)] K
- Enthalpy of fusion: (no data) kJ mol-1
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 188.8.131.52.25.8.2. The ground state electronic configuration of neutral Americium is [Rn].5f7.7s2 and the term symbol of Americium is 8S7/2.
- Pauling electronegativity: 1.3 (Pauling units)
- First ionisation energy: 578 kJ mol‑1
- Second ionisation energy: (no data) kJ mol‑1
Isolation: coming soon!
Americium isotopes Read more »