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Isotopes of Curium

List, data and properties of all known isotopes of Curium.

Content
Atomic properties
Decay properties
NMR active nuclides
Radiation protection
References
Curium isotopes

All atomic nuclei of the chemical element curium are summarized under curium isotopes; these consist of an atomic nucleus with 96 protons and in the uncharged state of 96 electrons. The difference between the individual curium isotopes lies in the number of neutrons in the nucleus.

Curium was first produced and characterized in 1944 in the form of the isotope Cm-242 by bombarding plutonium-239 with alpha particles.

The highly radioactive element, of which no stable isotopes are known, is only found in extremely small traces in nature. In particular, the short-lived curium isotopes 242 and 244 are used in technical applications in special radionuclide batteries, X-ray spectrometers and for the generation of other transuranic elements such as hassium or seaborgium.

Curium isotopes are obtained in special nuclear reactors.

 

Isotope Table: Curium

The two following tables list the most important data and properties of the Curium isotopes. Further information on the individual Curium isotopes is listed on separate pages and can be accessed via the link in column 1.

 

Atomic Properties

Isotope
Nuclide		ENAtomic Mass
[Nuclear Mass]
{Mass Excess}		Spin I
(h/2π)		Parent
123456
Curium-23223296Cm136
Curium-23323396Cm137233.050770(90) u
[232.9981137 u]
{47.29195 MeV}
Curium-23423496Cm138234.050161(19) u
[233.9975047 u]
{46.72467 MeV}		0+
Curium-23523596Cm139235.05157(22) u
[234.9989137 u]
{48.03715 MeV}		239Cf
Curium-23623696Cm140236.051375(20) u
[235.9987187 u]
{47.8555 MeV}		0+240Cf
Curium-23723796Cm141237.05287(8) u
[237.0002137 u]
{49.24809 MeV}		241Cf
Curium-23823896Cm142238.053082(13) u
[238.0004257 u]
{49.44556 MeV}		0+242Cf
Curium-23923996Cm143239.05491(6) u
[239.0022537 u]
{51.14834 MeV}		(7/2-)243Cf
Curium-24024096Cm144240.0555283(20) u
[240.002872 u]
{51.72428 MeV}		0+244Cf
240Bk
Curium-24124196Cm145241.0576512(17) u
[241.0049949 u]
{53.70175 MeV}		1/2+245Cf
241Bk
Curium-24224296Cm146242.0588343(12) u
[242.006178 u]
{54.8038 MeV}		0+246Cf
242Bk
242Am
Curium-24324396Cm147243.0613874(16) u
[243.0087311 u]
{57.18199 MeV}		5/2+247Cf
243Bk
Curium-243m243m96Cm147243.0613874(16) u
[243.0087311 u]
{57.18199 MeV}		1/2+
Curium-24424496Cm148244.0627507(12) u
[244.0100944 u]
{58.4519 MeV}		0+248Cf
244Bk
244Am
Curium-244m244m96Cm148244.0627507(12) u
[244.0100944 u]
{58.4519 MeV}		6+
Curium-24524596Cm149245.0654911(12) u
[245.0128348 u]
{61.00457 MeV}		7/2+249Cf
245Bk
245Am
Curium-245m245m96Cm149245.0654911(12) u
[245.0128348 u]
{61.00457 MeV}		1/2+
Curium-24624696Cm150246.0672221(16) u
[246.0145658 u]
{62.61698 MeV}		0+250Cf
246Bk
246Am
Curium-24724796Cm151247.070353(4) u
[247.0176967 u]
{65.5334 MeV}		9/2-251Cf
247Am
Curium-247m1247m196Cm151247.070353(4) u
[247.0176967 u]
{65.5334 MeV}		5/2+
Curium-247m2247m296Cm151247.070353(4) u
[247.0176967 u]
{65.5334 MeV}		1/2+
Curium-24824896Cm152248.0723491(25) u
[248.0196928 u]
{67.39275 MeV}		0+252Cf
248Bk
Curium-24924996Cm153249.0759540(25) u
[249.0232977 u]
{70.7507 MeV}		1/2+253Cf
Curium-249m249m96Cm153249.0759540(25) u
[249.0232977 u]
{70.7507 MeV}		7/2+
Curium-25025096Cm154250.078358(11) u
[250.0257017 u]
{72.99001 MeV}		0+254Cf
Curium-25125196Cm155251.082285(24) u
[251.0296287 u]
{76.64798 MeV}		(1/2+)
Curium-25225296Cm156252.08487(32) u
[252.0322137 u]
{79.0559 MeV}		0+

 

Radioactive Decay Properties

IsotopeRadioactive DecayExtern
Half-lifeDecay ModeProbabilityEnergy
789101112
Cm-232- ungelistet -AL
Cm-23323 sα 229Pu
EC, β+ 233Am		20
80		7.473(54) MeV
4.008(140) MeV		AL
Cm-23451(12) sα → 230Pu
EC/β+ → 234Am
SF div		ca. 40 %
ca. 20 %
ca. 40 %		7.365(9) MeV
2.26(16) MeV
AL
Cm-235~ 5 minAL
Cm-236~ 10 minα → 232Pu
EC → 236Am		?
?		7.067(5) MeV
1.81(11) MeV		AL
Cm-237~ 20 minAL
Cm-2382.2(4) hα → 234Pu
EC → 238Am
SF div		3.84(18) %
96.16(18) %
0.048(2) %		6.67(10) MeV
1.02(5) MeV
AL
Cm-2392.7(8) hα → 235Pu
EC → 239Am		< 0.01 %
> 99.99 %		6.54(5) MeV
1.76(5) MeV		AL
Cm-24027(1) dα → 236Pu
EC → 240Am
SF div		> 99.5 %
< 0.5 %
Spuren		6.3978(6) MeV
0.214(14) MeV
AL
Cm-24132.8(2) dα → 237Pu
EC → 241Am		1.0(1) %
99.0(1) %		6.1852(6) MeV
0.7674(12) MeV		AL
Cm-242162.8(2) dα → 238Pu
SF div		< 100 %
Spuren		6.21563(8) MeV
AL
Cm-24329.1(1) aα → 239Pu
EC → 243Am
SF div		99.71(3) %
0.29(3) %
Spuren		6.1688(10) MeV
0.007(2) MeV
AL
Cm-243m1.08(3) μsAL
Cm-24418.11(3) aα → 240Pu
SF div		ca. 100 %
Spuren		5.90160(3) MeV
AL
Cm-244m34(2) msIso → 244Cm100 %AL
Cm-2458423(74) aα → 241Pu
SF div		ca. 100 %
Spuren		5.6245(5) MeV
AL
Cm-245m0.29(2) μsAL
Cm-2464706(40) aα → 242Pu
SF div		99.97385(7) %
0.02615(7) %		5.4571(9)
AL
Cm-2471.56(5) × 107 aα → 243Pu100 %5.354(3) MeVAL
Cm-247m126.3(3) μs
Cm-247m2100.6(6) ns
Cm-2483.48(6) × 105 aα → 244Pu
SF div		91.61(16) %
8.39(16) %		5.16181(25) MeV
AL
Cm-24964.15(3) minβ- → 249Bk100 %0.9043(26) MeVAL
Cm-249m23 μs
Cm-2508300 aβ- → 250Bk
α → 246Pu
SF div		ca. 8 %
ca. 18 %
ca. 74 %		40(11) MeV
5.17(18) MeV
AL
Cm-25116.8(2) minβ- → 251Bk100 %1.42(2) MeVAL
Cm-252< 2 dAL

 

Notes (related to the columns):

1 - name of the nuclide, isotope.
2 - E: isotope symbol with mass number (superscript; number of nucleons) and atomic number (subscript; number of protons).
3 - N: number of neutrons.
4 - relative atomic mass of the Curium isotope (isotopic mass including electrons) and the mass of the atomic nucleus in square brackets (nuclear mass, nuclide mass without electrons), each related to 12C = 12.00000 [2]. In addition, the mass excess is given in MeV.
5 - nuclear spin I, unit: h/2π.
6 - source nuclides: Possible, assumed or actual source nuclides (mother nuclides, parent nuclides). If applicable, the corresponding decay modes can be found in the data for the respective starting nuclide.

7 - isotope notation in short form.
8 - decay: half-live of the Curium isotope (a = years; ; d = days; h = hours; min = minutes; s = seconds).
9 - decay mode: type of decay into the respective daughter nuclides with n = neutron emission; p = proton emission; α = alpha decay; β- = beta minus decay with electron emission; EC = electron capture; β+ = positron emission; ε = β+ and/or EC; Iso = isomeric transition; CD = cluster decay; SF = spontaneous decay.
10 - decay probability in percent (%).
11 - decay energy; Particle energy related to decay type.
12 - other information and notes: AL = Adopted Levels (link to external data [1]).

Miscellaneous:

()- Numbers in brackets: uncertainty to represent the spread of the reported value.
~ - Theoretical values or systematic trends.
  - unlisted-: Nuclides that have already been mentioned in the literature but for some reason can no longer be found in the current nuclide tables because their discovery e.g. has not confirmed.

 

Radiation Protection

According to the Radiation Protection Ordinance (StrlSchV 2018, Germany), the following values (columns 1 to 7) apply to the handling of Curium radionuclides:

NuclideLimit ValueHASS limitSCDaughter NuclidesHalf-life
Cm-238+107 Bq100 Bq/g2.4 h
Cm-240105 Bq100 Bq/g0,3 TBq27.0 d
Cm-241106 Bq10 Bq/g32.8 d
Cm-242105 Bq10 Bq/g0,04 TBq1 Bq cm-2162.9 d
Cm-243104 Bq1 Bq/g0,2 TBq0,1 Bq cm-230.0 a
Cm-244104 Bq1 Bq/g0,05 TBq0,1 Bq cm-218.0 a
Cm-245103 Bq0,1 Bq/g0,09 TBq0,1 Bq cm-28500 a
Cm-246103 Bq0,1 Bq/g0,2 TBq0,1 Bq cm-24700 a
Cm-247+104 Bq0,1 Bq/g0,1 Bq cm-2Pu-24316000000 a
Cm-248103 Bq0,1 Bq/g0,005 TBq0,01 Bq cm-2340000 a
Cm-249106 Bq1000 Bq/g64.2 min
Cm-250+103 Bq0,1 Bq/g8000 a

(HASS = High-Activity Sealed Radioactive Sources; SC = surface contamination)

 

Literature Sources and References

Properties of the Curium nucleides

[1] - NuDat: National Nuclear Data Center, Brookhaven National Laboratory, based on ENSDF and the Nuclear Wallet Cards.

[2] - G. Audi et. al.: The NUBASE evaluation of nuclear and decay properties. Nuclear Physics, (2003), DOI 10.1016/j.nuclphysa.2003.11.001.

[3] - Live Chart of Nuclides. Nuclear structure and decay data.

Curium: NMR properties

[4] - N. J. Stone: Table of nuclear magnetic dipole and electric quadrupole moments. Atomic Data and Nuclear Data Tables, (2005), DOI 10.1016/j.adt.2005.04.001.

[5] - Pekka Pyykkö: Year-2008 nuclear quadrupole moments. Molecular Physics, (2008), DOI 10.1080/00268970802018367.

[6] - Pekka Pyykkö: Year-2017 nuclear quadrupole moments. Molecular Physics, (2018), DOI 10.1080/00268976.2018.1426131.

[7] - N. J. Stone: Table of recommended nuclear magnetic dipole moments. IAEA, (2019).

More sources:

[8] - Isotopic abundances, atomic weights and isotopic masses: see respective keyword.

 

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