Curium

Curium (Cm)

Curium is the 96th element in the periodic table and has a symbol of Cm and atomic number of 96. It has an atomic weight of (247) and a mass number of 231. Curium has ninety-six protons and one hundred thirty-five neutrons in its nucleus, and ninety-six electrons in seven shells. It is located in group Actinides, period seven and block f of the periodic table. Radioactive metallic transuranic element. Belongs to actinoid series. Nine known isotopes, Cm-247 has a half-life of 1.64*10^7 years. First identified by Glenn T. Seaborg and associates in 1944, first produced by L.B. Werner and I. Perlman in 1947 by bombarding americium-241 with Neutrons. Named for Marie Curie.
Atomic Number96
Atomic Weight247
Mass Number231
Group
Period7
Blockf
Protons96 p+
Neutrons135 n0
Electrons96 e-
Animated Bohr Model of Cm (Curium)

Physical Properties

Atomic Radius
Molar Volume
18.28 cm³/mol
Covalent Radius
166 pm
Metallic Radius
Ionic Radius
97 pm
Crystal Radius
111 pm
Van der Waals Radius
245 pm
Density
13.51 g/cm³

Chemical Properties

Energy
Proton Affinity
Electron Affinity
Ionization Energy
5.9914 eV/particle
Ionization Energies of Cm (Curium)
Heat of Vaporization
Heat of Fusion
Heat of Formation
386 kJ/mol
Electrons
Electron Shells2, 8, 18, 32, 25, 9, 2
Bohr Model: Cm (Curium)
Valence Electrons2 ⓘ
Lewis Structure: Cm (Curium)
Electron Configuration[Rn] 5f7 6d1 7s2ⓘ
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 5f7 6d1 7s2
Enhanced Bohr Model of Cm (Curium)
Orbital Diagram of Cm (Curium)
Oxidation States3, 4, 5, 6
Electronegativity
Electrophilicity Index
States of Matter
PhaseSolid
Gas Phase
Boiling Point
Melting Point
1,618.15 K
Critical Pressure
Critical Temperature
Triple Point
Visual

Curium is a Silver. Cm has a CPK of #ffffff, Jmol of #785ce3, and MOLCAS GV of #785ce3. The Appearance of Element 96 is silvery metallic, glows purple in the dark.

Color
Silver
Appearancesilvery metallic, glows purple in the dark
Refractive Index
Thermodynamic Properties
Thermal Conductivity
Thermal Expansion
Molar Heat Capacity
Specific Heat Capacity
Heat Capacity Ratio (Adiabatic Index)
Electrical Properties
Type
Electrical Conductivity
Electrical Resistivity
Superconducting Point
Magnetism
Type
Magnetic Susceptibility (Mass)
Magnetic Susceptibility (Molar)
Magnetic Susceptibility (Volume)
Magnetic Ordering
Curie Point
Neel Point
Structure

The lattice angles of Curium are π/2, π/2, 2 π/3.

Crystal StructureSimple Hexagonal ()
Lattice Constant
Lattice Anglesπ/2, π/2, 2 π/3
Mechanical Properties
Hardness
Bulk Modulus
Shear Modulus
Young's Modulus
Poisson Ratio
Speed of Sound
Classification

The Glawe Number of Curium is 40. The Mendeleev Number of Cm is 28. The Pettifor Number of Element 96 is 41. The Goldschmidt Class of Curium (Cm) is synthetic.

CategoryActinides, Actinides
CAS Group
IUPAC Group
Glawe Number40
Mendeleev Number28
Pettifor Number41
Geochemical Class
Goldschmidt Classsynthetic

Other

The Dipole Polarizability of Curium is 144 plus or minus 25 a₀. The Allotropes of Cm is . The Neutron Cross Section of Element 96 is 60. The Quantum Numbers of Curium (Cm) is 9D2. The Space Group of Curium is 194 (P63/mmc).

Gas Basicity
Dipole Polarizability
144 ± 25 a₀
C6 Dispersion Coefficient
Allotropes
Neutron Cross Section
60
Neutron Mass Absorption
Quantum Numbers9D2
Space Group194 (P63/mmc)

Isotopes of Curium

Stable Isotopes0
Unstable Isotopes22
Natural Isotopes0

231Cm

Mass Number231
Neutron Number135
Relative Atomic Mass
231.050746 ± 0.000322 Da
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
Spin3/2
Quadrupole Moment
Discovery Year
Parity+
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)
α (α emission)

232Cm

Mass Number232
Neutron Number136
Relative Atomic Mass
232.04974 ± 0.000216 Da
G-Factor
0
Abundance
Radioactivity☢️ Radioactive
Half Life
Spin0
Quadrupole Moment
0
Discovery Year
Parity+
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)
α (α emission)

233Cm

Mass Number233
Neutron Number137
Relative Atomic Mass
233.050771485 ± 0.000087059 Da
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
27 ± 10 s
Spin3/2
Quadrupole Moment
Discovery Year2001
Parity+
Decay ModeIntensity
α (α emission)20%
β+ (β+ decay; β+ = ϵ + e+)80%

234Cm

Mass Number234
Neutron Number138
Relative Atomic Mass
234.050158568 ± 0.000018333 Da
G-Factor
0
Abundance
Radioactivity☢️ Radioactive
Half Life
52 ± 9 s
Spin0
Quadrupole Moment
0
Discovery Year2001
Parity+
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)71%
α (α emission)27%
SF (spontaneous fission)2%

235Cm

Mass Number235
Neutron Number139
Relative Atomic Mass
235.051545 ± 0.00011 Da
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
7 ± 3 m
Spin5/2
Quadrupole Moment
Discovery Year1981
Parity+
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)
α (α emission)4%

236Cm

Mass Number236
Neutron Number140
Relative Atomic Mass
236.051372112 ± 0.000018931 Da
G-Factor
0
Abundance
Radioactivity☢️ Radioactive
Half Life
6.8 ± 0.8 m
Spin0
Quadrupole Moment
0
Discovery Year2010
Parity+
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)82%
α (α emission)18%
SF (spontaneous fission)

237Cm

Mass Number237
Neutron Number141
Relative Atomic Mass
237.052868988 ± 0.00007987 Da
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
Spin5/2
Quadrupole Moment
Discovery Year2002
Parity+
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)
α (α emission)

238Cm

Mass Number238
Neutron Number142
Relative Atomic Mass
238.053081606 ± 0.000013133 Da
G-Factor
0
Abundance
Radioactivity☢️ Radioactive
Half Life
2.2 ± 0.4 h
Spin0
Quadrupole Moment
0
Discovery Year1994
Parity+
Decay ModeIntensity
ϵ (electron capture)
α (α emission)3.84%
SF (spontaneous fission)0.048%

239Cm

Mass Number239
Neutron Number143
Relative Atomic Mass
239.054908519 ± 0.000161107 Da
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
2.5 ± 0.4 h
Spin7/2
Quadrupole Moment
Discovery Year1952
Parity-
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
α (α emission)6.2%

240Cm

Mass Number240
Neutron Number144
Relative Atomic Mass
240.055528233 ± 0.000002045 Da
G-Factor
0
Abundance
Radioactivity☢️ Radioactive
Half Life
30.4 ± 3.7 d
Spin0
Quadrupole Moment
0
Discovery Year1949
Parity+
Decay ModeIntensity
α (α emission)100%
ϵ (electron capture)
SF (spontaneous fission)3.9%

241Cm

Mass Number241
Neutron Number145
Relative Atomic Mass
241.057651218 ± 0.000001725 Da
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
32.8 ± 0.2 d
Spin1/2
Quadrupole Moment
0
Discovery Year1952
Parity+
Decay ModeIntensity
ϵ (electron capture)99%
α (α emission)1%

242Cm

Mass Number242
Neutron Number146
Relative Atomic Mass
242.058834187 ± 0.000001224 Da
G-Factor
0
Abundance
Radioactivity☢️ Radioactive
Half Life
162.8 ± 0.2 d
Spin0
Quadrupole Moment
0
Discovery Year1949
Parity+
Decay ModeIntensity
α (α emission)100%
SF (spontaneous fission)6.2%
34Si1.1%
2β+ (double β+ decay)

243Cm

Mass Number243
Neutron Number147
Relative Atomic Mass
243.061387329 ± 0.000001605 Da
G-Factor
0.16 ± 0.032
Abundance
Radioactivity☢️ Radioactive
Half Life
29.1 ± 0.1 y
Spin5/2
Quadrupole Moment
Discovery Year1950
Parity+
Decay ModeIntensity
α (α emission)100%
ϵ (electron capture)0.29%
SF (spontaneous fission)5.3%

244Cm

Mass Number244
Neutron Number148
Relative Atomic Mass
244.062750622 ± 0.000001187 Da
G-Factor
0
Abundance
Radioactivity☢️ Radioactive
Half Life
18.11 ± 0.03 y
Spin0
Quadrupole Moment
0
Discovery Year1950
Parity+
Decay ModeIntensity
α (α emission)100%
SF (spontaneous fission)1.37%

245Cm

Mass Number245
Neutron Number149
Relative Atomic Mass
245.065491047 ± 0.000001233 Da
G-Factor
0.14285714285714 ± 0.028571428571429
Abundance
Radioactivity☢️ Radioactive
Half Life
8.25 ± 0.07 ky
Spin7/2
Quadrupole Moment
Discovery Year1954
Parity+
Decay ModeIntensity
α (α emission)100%
SF (spontaneous fission)6.1%

246Cm

Mass Number246
Neutron Number150
Relative Atomic Mass
246.067222016 ± 0.000001637 Da
G-Factor
0
Abundance
Radioactivity☢️ Radioactive
Half Life
4.706 ± 0.04 ky
Spin0
Quadrupole Moment
0
Discovery Year1954
Parity+
Decay ModeIntensity
α (α emission)99.97385%
SF (spontaneous fission)0.02615%

247Cm

Mass Number247
Neutron Number151
Relative Atomic Mass
247.070352678 ± 0.000004076 Da
G-Factor
0.08 ± 0.015555555555556
Abundance
Radioactivity☢️ Radioactive
Half Life
15.6 ± 0.5 My
Spin9/2
Quadrupole Moment
Discovery Year1954
Parity-
Decay ModeIntensity
α (α emission)100%

248Cm

Mass Number248
Neutron Number152
Relative Atomic Mass
248.072349086 ± 0.000002531 Da
G-Factor
0
Abundance
Radioactivity☢️ Radioactive
Half Life
348 ± 6 ky
Spin0
Quadrupole Moment
0
Discovery Year1956
Parity+
Decay ModeIntensity
α (α emission)91.61%
SF (spontaneous fission)8.39%
2β− (double β− decay)

249Cm

Mass Number249
Neutron Number153
Relative Atomic Mass
249.075953992 ± 0.000002545 Da
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
64.15 ± 0.03 m
Spin1/2
Quadrupole Moment
0
Discovery Year1956
Parity+
Decay ModeIntensity
β− (β− decay)100%

250Cm

Mass Number250
Neutron Number154
Relative Atomic Mass
250.078357541 ± 0.000011029 Da
G-Factor
0
Abundance
Radioactivity☢️ Radioactive
Half Life
Spin0
Quadrupole Moment
0
Discovery Year1966
Parity+
Decay ModeIntensity
SF (spontaneous fission)74%
α (α emission)
β− (β− decay)

251Cm

Mass Number251
Neutron Number155
Relative Atomic Mass
251.082284988 ± 0.000024367 Da
G-Factor
Abundance
Radioactivity☢️ Radioactive
Half Life
16.8 ± 0.2 m
Spin3/2
Quadrupole Moment
Discovery Year1978
Parity+
Decay ModeIntensity
β− (β− decay)100%

252Cm

Mass Number252
Neutron Number156
Relative Atomic Mass
252.08487 ± 0.00032 Da
G-Factor
0
Abundance
Radioactivity☢️ Radioactive
Half Life
Spin0
Quadrupole Moment
0
Discovery Year
Parity+
Decay ModeIntensity
β− (β− decay)
α (α emission)
Cm-Fluoreszenz

History

Curium was discovered by Glenn T. Seaborg, Ralph A. James and Albert Ghiorso in 1944 at the University of California, Berkeley. It was produced by bombarding plutonium with alpha particles during the Manhattan Project. Curium metal was produced only in 1951 by reduction of curium fluoride with barium. Curium is named after Madame Curie and her husband Pierre Curie

DiscoverersG.T.Seaborg, R.A.James, A.Ghiorso
Discovery LocationUnited States
Discovery Year1944
Etymology (Name Origin)Named in honor of Pierre and Marie Curie.
PronunciationKYOOR-i-em (English)
Curium is harmful due to its radioactivity
Curium accumulates in the bones, lungs and liver, where it promotes cancer

Uses

Curium is mainly used for scientific research purposes. Curium is a common starting material for the production of higher transuranic elements and transactinides. The most practical application of 244Cm is as α-particle source in the alpha particle X-ray spectrometers (APXS). It has no significant commercial applications.

Sources

Made by bombarding plutonium with helium ions. So radioactive it glows in the dark.

Abundance
Abundance in Earth's crust
Natural Abundance (Oceans)
Natural Abundance (Human Body)
0 %
Natural Abundance (Meteor)
0 %
Natural Abundance (Sun)
0 %
Abundance in Universe
0 %

Nuclear Screening Constants

Also Known As

  • Cm
  • element 96

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