Curium
Actinidesolidblock f
An actinide radioactive enough to glow purple in the dark, and the alpha source inside the X-ray spectrometers carried by the Mars rovers.
| Atomic number | 96 |
| Mass number (longest-lived isotope) | 247 g/mol |
| This element has no stable isotope, so it has no standard atomic weight. The figure above is the mass number of its longest-lived isotope — a convention, not a measurement of a natural mixture. | |
| Group · period | f-block series · 7 |
| Electron configuration | [Rn] 5f⁷ 6d¹ 7s² |
About Curium
Curium repeats gadolinium's trick one row down: a half-filled 5f⁷ shell is stable enough that the extra electron goes into 6d, giving [Rn] 5f⁷ 6d¹ 7s². Named for Marie and Pierre Curie, it was actually made before americium, in 1944, though wartime secrecy delayed the announcement. Curium-244 puts out about 3 W of alpha heat per gram, enough that samples glow, and curium-244 sources power the alpha particle X-ray spectrometers that determined the elemental composition of Martian rock on Sojourner, Spirit, Opportunity and Curiosity. Because it is a strong neutron emitter through spontaneous fission it is also one of the isotopes that makes handling spent fuel difficult decades after it leaves the reactor.
Moles from Mass (n = m/M)
Opens with M = 247 g/mol already filled in
Gas Density from Molar Mass
Opens with M = 247 g/mol already filled in
Faraday's Law of Electrolysis (m = QM/nF)
Opens with M = 247 g/mol already filled in
Ion Concentration as CaCO₃ Equivalent
Opens with EW = 247 g/mol already filled in
Acid Feed to Reduce Alkalinity
Opens with EW = 247 g/mol already filled in