Curium
actinideProperties
| Property | Value |
|---|---|
| Atomic Mass | 247 amu |
| Category | actinide |
| Period | 7 |
| Electron Configuration | [Rn] 5f7 6d1 7s2 |
| Electronegativity | 1.3 (Pauling) |
| Oxidation States | 4, 3 |
| Melting Point | 1613 K (1339.8 °C) |
| Boiling Point | 3383 K (3109.8 °C) |
| Density | 13.51 g/cm³ |
| Discovered By | Glenn T. Seaborg, Ralph A. James, Albert Ghiorso (1944) |
About Curium
Curium has the half-filled 5f⁷ configuration that mirrors gadolinium one row up, and it gets the same magnetic and stability bonus — the +3 oxidation state dominates because going to +4 means breaking that high-spin symmetry. The isotope working chemists actually care about is ²⁴⁴Cm: 18.1-year half-life, almost pure alpha emitter, putting out about 2.8 W of decay heat per gram. That power density is what made it the source for the alpha-particle X-ray spectrometers (APXS) on Spirit, Opportunity, and Curiosity — the instrument's pencil of 5.8 MeV alphas excites characteristic X-ray fluorescence from whatever Martian rock is pressed against it, and the spectrum reads back elemental composition without needing any moving parts or sample prep. Producing curium means months of irradiating ²⁴³Am or ²³⁹Pu in a high-flux reactor, then a long sequence of solvent extractions to separate it from the surrounding actinides; the world inventory is measured in grams. Crystals containing it glow faint reddish-purple in the dark from radioluminescence of the trapping matrix.
Fun Fact
Curium has helped explore Mars — the alpha particle X-ray spectrometers on NASA's Mars rovers use curium-244 to bombard Martian rocks with alpha particles, revealing the chemical composition of another planet's surface.
Common Uses
- Alpha particle X-ray spectrometers on Mars rovers
- Compact radioisotope power sources
- Neutron sources for scientific research
- Production of heavier transuranium elements
- Research into actinide physics and chemistry