Curium

Curium (Cm)

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-
Cm-Fluoreszenz.png Animated Bohr Model of Cm (Curium) Enhanced Bohr Model of Cm (Curium) Bohr Model: Cm (Curium) Orbital Diagram of Cm (Curium)

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
Energy
Proton Affinity
Electron Affinity
Ionization Energy
Heat of Vaporization
Heat of Fusion
Heat of Formation
386 kJ/mol
Electrons
Electron Shells2, 8, 18, 32, 25, 9, 2
Valence Electrons4
Electron Configuration[Rn] 5f7 6d1 7s2
Oxidation States3, 4, 5, 6
Electronegativity
Electrophilicity
Phases
PhaseSolid
Gas Phase
Boiling Point
Melting Point
1,618.15 K
Critical Pressure
Critical Temperature
Triple Point
Visual
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
Crystal StructureSimple Hexagonal ()
Lattice Constant
Lattice Anglesπ/2, π/2, 2 π/3
Mechanical Properties
Hardness
Bulk Modulus
Shear Modulus
Young Modulus
Poisson Ratio
Speed of Sound
Classification
CategoryActinides, Actinides
CAS Group
IUPAC Group
Glawe Number40
Mendeleev Number28
Pettifor Number41
Geochemical Class
Goldschmidt Classsynthetic
Other
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
Radioactive Isotopes22

231Cm

AbundanceRadioactive ☢️
Relative Atomic Mass
231.050746 ± 0.000322 Da
Mass Number231
G-Factor
Half Life
Spin3/2
Quadrupole Moment
Discovery Year
Parity+

231Cm Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)%
α (α emission)%

232Cm

AbundanceRadioactive ☢️
Relative Atomic Mass
232.04974 ± 0.000216 Da
Mass Number232
G-Factor
0
Half Life
Spin0
Quadrupole Moment
0
Discovery Year
Parity+

232Cm Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)%
α (α emission)%

233Cm

AbundanceRadioactive ☢️
Relative Atomic Mass
233.050771485 ± 0.000087059 Da
Mass Number233
G-Factor
Half Life
27 ± 10 s
Spin3/2
Quadrupole Moment
Discovery Year2001
Parity+

233Cm Decay Modes
Decay ModeIntensity
α (α emission)20%
β+ (β+ decay; β+ = ϵ + e+)80%

234Cm

AbundanceRadioactive ☢️
Relative Atomic Mass
234.050158568 ± 0.000018333 Da
Mass Number234
G-Factor
0
Half Life
52 ± 9 s
Spin0
Quadrupole Moment
0
Discovery Year2001
Parity+

234Cm Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)71%
α (α emission)27%
SF (spontaneous fission)2%

235Cm

AbundanceRadioactive ☢️
Relative Atomic Mass
235.051545 ± 0.00011 Da
Mass Number235
G-Factor
Half Life
7 ± 3 m
Spin5/2
Quadrupole Moment
Discovery Year1981
Parity+

235Cm Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)%
α (α emission)4%

236Cm

AbundanceRadioactive ☢️
Relative Atomic Mass
236.051372112 ± 0.000018931 Da
Mass Number236
G-Factor
0
Half Life
6.8 ± 0.8 m
Spin0
Quadrupole Moment
0
Discovery Year2010
Parity+

236Cm Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)82%
α (α emission)18%
SF (spontaneous fission)%

237Cm

AbundanceRadioactive ☢️
Relative Atomic Mass
237.052868988 ± 0.00007987 Da
Mass Number237
G-Factor
Half Life
Spin5/2
Quadrupole Moment
Discovery Year2002
Parity+

237Cm Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)%
α (α emission)%

238Cm

AbundanceRadioactive ☢️
Relative Atomic Mass
238.053081606 ± 0.000013133 Da
Mass Number238
G-Factor
0
Half Life
2.2 ± 0.4 h
Spin0
Quadrupole Moment
0
Discovery Year1994
Parity+

238Cm Decay Modes
Decay ModeIntensity
ϵ (electron capture)%
α (α emission)3.84%
SF (spontaneous fission)0.048%

239Cm

AbundanceRadioactive ☢️
Relative Atomic Mass
239.054908519 ± 0.000161107 Da
Mass Number239
G-Factor
Half Life
2.5 ± 0.4 h
Spin7/2
Quadrupole Moment
Discovery Year1952
Parity-

239Cm Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
α (α emission)6.2%

240Cm

AbundanceRadioactive ☢️
Relative Atomic Mass
240.055528233 ± 0.000002045 Da
Mass Number240
G-Factor
0
Half Life
30.4 ± 3.7 d
Spin0
Quadrupole Moment
0
Discovery Year1949
Parity+

240Cm Decay Modes
Decay ModeIntensity
α (α emission)100%
ϵ (electron capture)%
SF (spontaneous fission)3.9%

241Cm

AbundanceRadioactive ☢️
Relative Atomic Mass
241.057651218 ± 0.000001725 Da
Mass Number241
G-Factor
Half Life
32.8 ± 0.2 d
Spin1/2
Quadrupole Moment
0
Discovery Year1952
Parity+

241Cm Decay Modes
Decay ModeIntensity
ϵ (electron capture)99%
α (α emission)1%

242Cm

AbundanceRadioactive ☢️
Relative Atomic Mass
242.058834187 ± 0.000001224 Da
Mass Number242
G-Factor
0
Half Life
162.8 ± 0.2 d
Spin0
Quadrupole Moment
0
Discovery Year1949
Parity+

242Cm Decay Modes
Decay ModeIntensity
α (α emission)100%
SF (spontaneous fission)6.2%
34Si1.1%
+ (double β+ decay)%

243Cm

AbundanceRadioactive ☢️
Relative Atomic Mass
243.061387329 ± 0.000001605 Da
Mass Number243
G-Factor
0.16 ± 0.032
Half Life
29.1 ± 0.1 y
Spin5/2
Quadrupole Moment
Discovery Year1950
Parity+

243Cm Decay Modes
Decay ModeIntensity
α (α emission)100%
ϵ (electron capture)0.29%
SF (spontaneous fission)5.3%

244Cm

AbundanceRadioactive ☢️
Relative Atomic Mass
244.062750622 ± 0.000001187 Da
Mass Number244
G-Factor
0
Half Life
18.11 ± 0.03 y
Spin0
Quadrupole Moment
0
Discovery Year1950
Parity+

244Cm Decay Modes
Decay ModeIntensity
α (α emission)100%
SF (spontaneous fission)1.37%

245Cm

AbundanceRadioactive ☢️
Relative Atomic Mass
245.065491047 ± 0.000001233 Da
Mass Number245
G-Factor
0.14285714285714 ± 0.028571428571429
Half Life
8.25 ± 0.07 ky
Spin7/2
Quadrupole Moment
Discovery Year1954
Parity+

245Cm Decay Modes
Decay ModeIntensity
α (α emission)100%
SF (spontaneous fission)6.1%

246Cm

AbundanceRadioactive ☢️
Relative Atomic Mass
246.067222016 ± 0.000001637 Da
Mass Number246
G-Factor
0
Half Life
4.706 ± 0.04 ky
Spin0
Quadrupole Moment
0
Discovery Year1954
Parity+

246Cm Decay Modes
Decay ModeIntensity
α (α emission)99.97385%
SF (spontaneous fission)0.02615%

247Cm

AbundanceRadioactive ☢️
Relative Atomic Mass
247.070352678 ± 0.000004076 Da
Mass Number247
G-Factor
0.08 ± 0.015555555555556
Half Life
15.6 ± 0.5 My
Spin9/2
Quadrupole Moment
Discovery Year1954
Parity-

247Cm Decay Modes
Decay ModeIntensity
α (α emission)100%

248Cm

AbundanceRadioactive ☢️
Relative Atomic Mass
248.072349086 ± 0.000002531 Da
Mass Number248
G-Factor
0
Half Life
348 ± 6 ky
Spin0
Quadrupole Moment
0
Discovery Year1956
Parity+

248Cm Decay Modes
Decay ModeIntensity
α (α emission)91.61%
SF (spontaneous fission)8.39%
(double β decay)%

249Cm

AbundanceRadioactive ☢️
Relative Atomic Mass
249.075953992 ± 0.000002545 Da
Mass Number249
G-Factor
Half Life
64.15 ± 0.03 m
Spin1/2
Quadrupole Moment
0
Discovery Year1956
Parity+

249Cm Decay Modes
Decay ModeIntensity
β (β decay)100%

250Cm

AbundanceRadioactive ☢️
Relative Atomic Mass
250.078357541 ± 0.000011029 Da
Mass Number250
G-Factor
0
Half Life
Spin0
Quadrupole Moment
0
Discovery Year1966
Parity+

250Cm Decay Modes
Decay ModeIntensity
SF (spontaneous fission)74%
α (α emission)%
β (β decay)%

251Cm

AbundanceRadioactive ☢️
Relative Atomic Mass
251.082284988 ± 0.000024367 Da
Mass Number251
G-Factor
Half Life
16.8 ± 0.2 m
Spin3/2
Quadrupole Moment
Discovery Year1978
Parity+

251Cm Decay Modes
Decay ModeIntensity
β (β decay)100%

252Cm

AbundanceRadioactive ☢️
Relative Atomic Mass
252.08487 ± 0.00032 Da
Mass Number252
G-Factor
0
Half Life
Spin0
Quadrupole Moment
0
Discovery Year
Parity+

252Cm Decay Modes
Decay ModeIntensity
β (β decay)%
α (α emission)%

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
Abundance in Oceans
Abundance in Human Body
0 %
Abundance in Meteor
0 %
Abundance in Sun
0 %
Abundance in Universe
0 %

Nuclear Screening Constants