Curium: the essentials
Curium is a hard, brittle, radioactive silvery metal. It does not occur in nature and must be made in a nuclear reactor by neutron capture reactions from plutonium and americium isotopes. It tarnishes slowly in dry air at room temperature. Curium was first produced in 1944 at the University of California, Berkeley in the USA in a cyclotron by bombarding plutonium-239 (239Pu) with α-particles. It was isolated in visible quantities as the hydroxide, Cm(OH)3, in 1947.
Most compounds of Cm(III) are faintly yellow. If curium enters the body it accumulates in the bones, and is therefore very toxic as its radiation destroys the red-cell forming mechanism. Curium is a radioactive rare earth metal. The most stable isotope is 247Cm which has a half-life of 16 million years. Curium is probably present in uranium ores. It has a few specialised uses but only a few of its compounds are known.
Curium: historical information
Curium was identified by Seaborg and others in 1944 as a result of helium ion bombardment of the plutonium isotope 239Pu. Three years later visible amounts of the hydroxide were isolated by Werner and Perlman. In 1951, the same workers prepared curium in its elemental form for the first time.
Curium around us Read more »
Curium has no biological role.
Curium is radioactive but is not present in the geosphere in any significant quantity.
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Physical properties Read more »
- Density of solid: 13510 kg m-3
- Molar volume: 18.05 cm3
- Thermal conductivity: 10 (estimate) W m‑1 K‑1
Heat properties Read more »
- Melting point: 1613 [1340 °C (2444 °F)] K
- Boiling point: 3383 [3110 °C (5630 °F)] K
- Enthalpy of fusion: (no data) kJ mol-1
Crystal structure Read more »
The solid state structure of curium is: hcp (hexagonal close-packed).
Curium: orbital properties Read more »
Curium atoms have 96 electrons and the shell structure is 220.127.116.11.25.9.2. The ground state electronic configuration of neutral Curium is [Rn].5f7.6d1.7s2 and the term symbol of Curium is 9D2.
- Pauling electronegativity: 1.3 (Pauling units)
- First ionisation energy: 581 kJ mol‑1
- Second ionisation energy: (no data) kJ mol‑1
Isolation: coming soon!
Curium isotopes Read more »