More Chemistry
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 Nuclide | E | N | Atomic Mass [Nuclear Mass] {Mass Excess} | Spin I (h/2π) | Parent |
---|---|---|---|---|---|
1 | 2 | 3 | 4 | 5 | 6 |
Curium-232 | 23296Cm | 136 | |||
Curium-233 | 23396Cm | 137 | 233.050770(90) u [232.9981137 u] {47.29195 MeV} | ||
Curium-234 | 23496Cm | 138 | 234.050161(19) u [233.9975047 u] {46.72467 MeV} | 0+ | |
Curium-235 | 23596Cm | 139 | 235.05157(22) u [234.9989137 u] {48.03715 MeV} | 239Cf | |
Curium-236 | 23696Cm | 140 | 236.051375(20) u [235.9987187 u] {47.8555 MeV} | 0+ | 240Cf |
Curium-237 | 23796Cm | 141 | 237.05287(8) u [237.0002137 u] {49.24809 MeV} | 241Cf | |
Curium-238 | 23896Cm | 142 | 238.053082(13) u [238.0004257 u] {49.44556 MeV} | 0+ | 242Cf |
Curium-239 | 23996Cm | 143 | 239.05491(6) u [239.0022537 u] {51.14834 MeV} | (7/2-) | 243Cf |
Curium-240 | 24096Cm | 144 | 240.0555283(20) u [240.002872 u] {51.72428 MeV} | 0+ | 244Cf 240Bk |
Curium-241 | 24196Cm | 145 | 241.0576512(17) u [241.0049949 u] {53.70175 MeV} | 1/2+ | 245Cf 241Bk |
Curium-242 | 24296Cm | 146 | 242.0588343(12) u [242.006178 u] {54.8038 MeV} | 0+ | 246Cf 242Bk 242Am |
Curium-243 | 24396Cm | 147 | 243.0613874(16) u [243.0087311 u] {57.18199 MeV} | 5/2+ | 247Cf 243Bk |
Curium-243m | 243m96Cm | 147 | 243.0613874(16) u [243.0087311 u] {57.18199 MeV} | 1/2+ | |
Curium-244 | 24496Cm | 148 | 244.0627507(12) u [244.0100944 u] {58.4519 MeV} | 0+ | 248Cf 244Bk 244Am |
Curium-244m | 244m96Cm | 148 | 244.0627507(12) u [244.0100944 u] {58.4519 MeV} | 6+ | |
Curium-245 | 24596Cm | 149 | 245.0654911(12) u [245.0128348 u] {61.00457 MeV} | 7/2+ | 249Cf 245Bk 245Am |
Curium-245m | 245m96Cm | 149 | 245.0654911(12) u [245.0128348 u] {61.00457 MeV} | 1/2+ | |
Curium-246 | 24696Cm | 150 | 246.0672221(16) u [246.0145658 u] {62.61698 MeV} | 0+ | 250Cf 246Bk 246Am |
Curium-247 | 24796Cm | 151 | 247.070353(4) u [247.0176967 u] {65.5334 MeV} | 9/2- | 251Cf 247Am |
Curium-247m1 | 247m196Cm | 151 | 247.070353(4) u [247.0176967 u] {65.5334 MeV} | 5/2+ | |
Curium-247m2 | 247m296Cm | 151 | 247.070353(4) u [247.0176967 u] {65.5334 MeV} | 1/2+ | |
Curium-248 | 24896Cm | 152 | 248.0723491(25) u [248.0196928 u] {67.39275 MeV} | 0+ | 252Cf 248Bk |
Curium-249 | 24996Cm | 153 | 249.0759540(25) u [249.0232977 u] {70.7507 MeV} | 1/2+ | 253Cf |
Curium-249m | 249m96Cm | 153 | 249.0759540(25) u [249.0232977 u] {70.7507 MeV} | 7/2+ | |
Curium-250 | 25096Cm | 154 | 250.078358(11) u [250.0257017 u] {72.99001 MeV} | 0+ | 254Cf |
Curium-251 | 25196Cm | 155 | 251.082285(24) u [251.0296287 u] {76.64798 MeV} | (1/2+) | |
Curium-252 | 25296Cm | 156 | 252.08487(32) u [252.0322137 u] {79.0559 MeV} | 0+ |
Isotope | Radioactive Decay | Extern | |||
---|---|---|---|---|---|
Half-life | Decay Mode | Probability | Energy | ||
7 | 8 | 9 | 10 | 11 | 12 |
Cm-232 | - ungelistet - | AL | |||
Cm-233 | 23 s | α 229Pu EC, β+ 233Am | 20 80 | 7.473(54) MeV 4.008(140) MeV | AL |
Cm-234 | 51(12) s | α → 230Pu EC/β+ → 234Am SF div | ca. 40 % ca. 20 % ca. 40 % | 7.365(9) MeV 2.26(16) MeV | AL |
Cm-235 | ~ 5 min | AL | |||
Cm-236 | ~ 10 min | α → 232Pu EC → 236Am | ? ? | 7.067(5) MeV 1.81(11) MeV | AL |
Cm-237 | ~ 20 min | AL | |||
Cm-238 | 2.2(4) h | α → 234Pu EC → 238Am SF div | 3.84(18) % 96.16(18) % 0.048(2) % | 6.67(10) MeV 1.02(5) MeV | AL |
Cm-239 | 2.7(8) h | α → 235Pu EC → 239Am | < 0.01 % > 99.99 % | 6.54(5) MeV 1.76(5) MeV | AL |
Cm-240 | 27(1) d | α → 236Pu EC → 240Am SF div | > 99.5 % < 0.5 % Spuren | 6.3978(6) MeV 0.214(14) MeV | AL |
Cm-241 | 32.8(2) d | α → 237Pu EC → 241Am | 1.0(1) % 99.0(1) % | 6.1852(6) MeV 0.7674(12) MeV | AL |
Cm-242 | 162.8(2) d | α → 238Pu SF div | < 100 % Spuren | 6.21563(8) MeV | AL |
Cm-243 | 29.1(1) a | α → 239Pu EC → 243Am SF div | 99.71(3) % 0.29(3) % Spuren | 6.1688(10) MeV 0.007(2) MeV | AL |
Cm-243m | 1.08(3) μs | AL | |||
Cm-244 | 18.11(3) a | α → 240Pu SF div | ca. 100 % Spuren | 5.90160(3) MeV | AL |
Cm-244m | 34(2) ms | Iso → 244Cm | 100 % | AL | |
Cm-245 | 8423(74) a | α → 241Pu SF div | ca. 100 % Spuren | 5.6245(5) MeV | AL |
Cm-245m | 0.29(2) μs | AL | |||
Cm-246 | 4706(40) a | α → 242Pu SF div | 99.97385(7) % 0.02615(7) % | 5.4571(9) | AL |
Cm-247 | 1.56(5) × 107 a | α → 243Pu | 100 % | 5.354(3) MeV | AL |
Cm-247m1 | 26.3(3) μs | ||||
Cm-247m2 | 100.6(6) ns | ||||
Cm-248 | 3.48(6) × 105 a | α → 244Pu SF div | 91.61(16) % 8.39(16) % | 5.16181(25) MeV | AL |
Cm-249 | 64.15(3) min | β- → 249Bk | 100 % | 0.9043(26) MeV | AL |
Cm-249m | 23 μs | ||||
Cm-250 | 8300 a | β- → 250Bk α → 246Pu SF div | ca. 8 % ca. 18 % ca. 74 % | 40(11) MeV 5.17(18) MeV | AL |
Cm-251 | 16.8(2) min | β- → 251Bk | 100 % | 1.42(2) MeV | AL |
Cm-252 | < 2 d | AL |
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.
According to the Radiation Protection Ordinance (StrlSchV 2018, Germany), the following values (columns 1 to 7) apply to the handling of Curium radionuclides:
Nuclide | Limit Value | HASS limit | SC | Daughter Nuclides | Half-life | |
---|---|---|---|---|---|---|
Cm-238+ | 107 Bq | 100 Bq/g | 2.4 h | |||
Cm-240 | 105 Bq | 100 Bq/g | 0,3 TBq | 27.0 d | ||
Cm-241 | 106 Bq | 10 Bq/g | 32.8 d | |||
Cm-242 | 105 Bq | 10 Bq/g | 0,04 TBq | 1 Bq cm-2 | 162.9 d | |
Cm-243 | 104 Bq | 1 Bq/g | 0,2 TBq | 0,1 Bq cm-2 | 30.0 a | |
Cm-244 | 104 Bq | 1 Bq/g | 0,05 TBq | 0,1 Bq cm-2 | 18.0 a | |
Cm-245 | 103 Bq | 0,1 Bq/g | 0,09 TBq | 0,1 Bq cm-2 | 8500 a | |
Cm-246 | 103 Bq | 0,1 Bq/g | 0,2 TBq | 0,1 Bq cm-2 | 4700 a | |
Cm-247+ | 104 Bq | 0,1 Bq/g | 0,1 Bq cm-2 | Pu-243 | 16000000 a | |
Cm-248 | 103 Bq | 0,1 Bq/g | 0,005 TBq | 0,01 Bq cm-2 | 340000 a | |
Cm-249 | 106 Bq | 1000 Bq/g | 64.2 min | |||
Cm-250+ | 103 Bq | 0,1 Bq/g | 8000 a |
(HASS = High-Activity Sealed Radioactive Sources; SC = surface contamination)
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.
Last update: 2022-12-12
Perma link: https://www.chemlin.org/chemical-elements/curium-isotopes.php
© 1996 - 2023 ChemLin