Curium

Radioactive and Artificially Produced Curium was first produced by Glenn T. Seaborg, Ralph A. James and Albert Ghiorso, working at the University of California, Berkeley, in 1944. They bombarded atoms of plutonium-239, an isotope of plutonium, with alpha particles that had been accelerated in a device called a cyclotron. This produced atoms of curium-242 and one free neutron. Curium-242 has a half-life of about 163 days and decays into plutonium-238 through alpha decay or decays through spontaneous fission. Curium's most stable isotope, curium-247, has a half-life of about 15,600,000 years. It decays into plutonium-243 through alpha decay. Since only milligram amounts of curium have ever been produced, there are currently no commercial applications for it, although it might be used in radioisotope thermoelectric generators in the future. Curium is primarily used for basic scientific research. Scientists have produced several curium compounds. They include: curium dioxide (CmO2), curium trioxide (Cm2O3), curium bromide (CmBr3), curium chloride (CmCl3), curium chloride (CmCl3), curium tetrafluoride (CmF4) and curium iodide (CmI3). As with the element, the compounds currently have no commercial applications and are primarily used for basic scientific research.
 * Curium**
 * Atomic Number:** 96
 * Atomic Weight:** 247
 * Melting Point:** 1618 K (1345°C or 2453°F)
 * Boiling Point:** ~3400 K (~3100°C or ~5600°F)
 * Density:** 13.51 grams per cubic centimeter
 * Phase at Room Temperature:** Solid
 * Element Classification:** Metal
 * Period Number:** 7 **Group Number:** none **Group Name:** Actinide
 * What's in a name?** Named after the scientists Pierre and Marie Curie.
 * Say what?** Curium is pronounced as **KYOOR-ee-em**.
 * History and Uses:**
 * Estimated Crustal Abundance:** Not Applicable
 * Estimated Oceanic Abundance:** Not Applicable
 * Number of Stable Isotopes:** 0
 * Ionization Energy:** 6.02 eV
 * Oxidation State:** +3

Curium is radioactive and only available in small amounts. Its uses are therefore rather specialist. For instance, curium was used as a thermoelectric power source and curium as 244Cm was the alpha particle source for the Alpha Proton X-Ray Spectrometer on the Mars Rover

Curium is a [|transuranic] [|radioactive] [|chemical element] with the symbol **Cm** and [|atomic number] 96. This [|radioactive] [|transuranic element] of the [|actinide] series was named after [|Marie Skłodowska-Curie] and her husband [|Pierre Curie]. Curium was first intentionally produced and identified in July 1944 by the group of [|Glenn T. Seaborg] at the [|University of California, Berkeley]. The discovery was kept secret and only released to the public in November 1945. Most curium is produced by bombarding [|uranium] or [|plutonium] with [|neutrons] in [|nuclear reactors] – one [|tonne] of spent [|nuclear fuel] contains about 20 grams of curium. Curium is a hard, dense silvery metal with a relatively high melting point and boiling point for an actinide. Whereas it is [|paramagnetic] at [|ambient conditions], it becomes [|antiferromagnetic] upon cooling, and other magnetic transitions are also observed for many curium compounds. In compounds, curium usually exhibits [|valence] +3 and sometimes +4, and the +3 valence is predominant in solutions. Curium readily oxidizes, and its oxides are a dominant form of this element. It forms strongly [|fluorescent] complexes with various organic compounds, but there is no evidence of its incorporation into [|bacteria] and [|archaea]. When introduced into the human body, curium accumulates in the bones, lungs and liver where it promotes [|cancer]. About 20 [|radioisotopes] and 7 [|nuclear isomers] between 233Cm and 252Cm are known for curium, and no stable [|isotopes]. All known [|isotopes] of curium are radioactive and have a small [|critical mass] for a sustained [|nuclear chain reaction]. They predominantly emit [|α-particles], and the heat released in this process can potentially produce electricity in [|radioisotope thermoelectric generators]. This application is hindered by the scarcity, high cost and radioactivity of curium isotopes. Curium is used in production of heavier actinides and of the 238Pu [|radionuclide] for power sources in [|artificial pacemakers]. It served as the [|α-source] in the [|alpha particle X-ray spectrometers] installed on the [|Sojourner], [|Mars], [|Mars 96], [|Athena], [|Spirit] and [|Opportunity rovers] to analyze the composition and structure of the rocks on the surface of [|Mars] and the [|Moon]. Such a spectrometer will also be used by the [|Philae lander] of the [|Rosetta] spacecraft to probe the surface of the [|67P/Churyumov-Gerasimenko] [|comet].



Currently, curium is not used as a nuclear fuel owing to its low availability and high price.[42home] 245Cm and 247Cm have a very small critical mass and therefore could be used in portable nuclear weapons, but none have been reported thus far. Curium-243 is not suitable for this purpose because of its short half-life and strong α emission which would result in excessive heat.[43home] Curium-247 would be highly suitable, having a half-life 647 times that of plutonium-239.