Curium Element Facts

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States
Energies
Oxidation & Electrons
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96 Cm 247 Curium

Curium is Radioactive.

Name: Curium
Type: Actinide
Density @ 293 K: 13.5 g/cm³

Discovery of Curium
Curium was the third synthetic transuranium element of the actinide series to be discovered.

It was discovered by Glenn T. Seaborg, Ralph A.James, and Albert Ghiorso in 1944. Curium-242 (half-life 162.8 days) was produced by bombarding plutonium-239 with alpha particles in the Berkeley, California, 60-inch cyclotron. Each nuclear reaction produced a neutron in addition to an atom of curium-242. ⁽¹⁾

The element was chemically identified at the metallurgical laboratory at the University of Chicago.

The researchers at first referred to curium as "delirium" owing to the difficulties they encountered trying to isolate it from another new element with which it was very closely associated, americium - or "pandemonium" as it was first called.

Symbol: Cm
Atomic weight: 247
Atomic volume: 18.28 cm³/mol

State (s, l, g): solid
Melting point: 1613 K   (1340 ^oC)

Boiling point: 3373 K   (3100 ^oC)

Specific heat capacity: J g^-1 K^-1
Heat of fusion: kJ mol^-1
1^st ionization energy: 581 kJ mol^-1
3^rd ionization energy: kJ mol^-1

Heat of atomization: kJ mol^-1
Heat of vaporization: kJ mol^-1
2^nd ionization energy: kJ mol^-1
Electron affinity: kJ mol^-1

Shells: 2,8,18,32,25,9,2
Minimum oxidation number: 0
Min. common oxidation no.: 0
Electronegativity (Pauling Scale): 1.3

Electron configuration: [Rn] 5f⁷ 6d¹ 7s²
Maximum oxidation number: 4
Max. common oxidation no.: 3
Polarizability volume: 23 ų

Structure: fcc: face-centered cubic
Hardness: mohs

Color: silvery-white


Harmful effects:
Curium is harmful due to its radioactivity. It accumulates in bones and destroys the marrow, stopping the formation of red blood cells.

Characteristics:
Curium is a hard, dense radioactive silvery-white metal. It tarnishes slowly in dry air at room temperature. Most compounds of trivalent curium are slightly yellow in color.

Curium is highly radioactive and it glows red in the dark. ⁽⁴⁾

Uses:
Curium is mainly used for scientific research purposes. Curium-244 was used in the Alpha Proton X-ray Spectrometer (APXS) which measured the abundance of chemical elements in rocks and soils on Mars. Curium-244 is a strong alpha emitter and is being studied as a potential power source in radioisotope thermoelectric generators (RTGs) for use in spacecraft and other remote applications.

Reaction with air:
Reaction with 15 M HNO₃:
Oxide(s): CmO, Cm₂O₃, CmO₂
Hydride(s): CmH₂

Reaction with 6 M HCl:
Reaction with 6 M NaOH:
Chloride(s): CmCl₃

Atomic radius: 174 pm
Ionic radius (2+ ion): pm
Ionic radius (2- ion): pm

Ionic radius (1+ ion): pm
Ionic radius (3+ ion): 111 pm
Ionic radius (1- ion): pm

Thermal conductivity: W m^-1 K^-1

Electrical conductivity: x 10⁶ S cm^-1