Isotopes of curium

Template:Short description Template:Infobox curium isotopes Curium (₉₆Cm) is an artificial element with an atomic number of 96. Because it is an artificial element, a standard atomic weight cannot be given, and it has no stable isotopes. The first isotope synthesized was ²⁴²Cm in 1944, which has 146 neutrons.

There are 19 known radioisotopes ranging from ²³³Cm to ²⁵¹Cm. There are also ten known nuclear isomers. The longest-lived isotope is ²⁴⁷Cm, with half-life 15.6 million years – orders of magnitude longer than that of any known isotope beyond curium, and long enough to study as a possible extinct radionuclide that would be produced by the r-process. The longest-lived known isomer is ^246mCm with a half-life of 1.12 seconds.

List of isotopes

Template:Isotopes table |-id=Curium-233 | rowspan=2|²³³Cm | rowspan=2 style="text-align:right" | 96 | rowspan=2 style="text-align:right" | 137 | rowspan=2|233.05077(9) | rowspan=2|Template:Val | β⁺ (80%) | ²³³Am | rowspan=2|3/2+# |- | α (20%) | ²²⁹Pu |-id=Curium-234 | rowspan=3|²³⁴Cm | rowspan=3 style="text-align:right" | 96 | rowspan=3 style="text-align:right" | 138 | rowspan=3|234.050159(18) | rowspan=3|Template:Val | β⁺ (71%) | ²³⁴Am | rowspan=3|0+ |- | α (27%) | ²³⁰Pu |- | SF (2%) | (various) |-id=Curium-235 | rowspan=2|²³⁵Cm | rowspan=2 style="text-align:right" | 96 | rowspan=2 style="text-align:right" | 139 | rowspan=2|235.05155(11)# | rowspan=2|Template:Val | β⁺? (96%) | ²³⁵Am | rowspan=2|5/2+# |- | α (4%) | ²³¹Pu |-id=Curium-236 | rowspan=2|²³⁶Cm | rowspan=2 style="text-align:right" | 96 | rowspan=2 style="text-align:right" | 140 | rowspan=2|236.051372(19) | rowspan=2|Template:Val | β⁺ (82%) | ²³⁶Am | rowspan=2|0+ |- | α (18%) | ²³²Pu |-id=Curium-237 | ²³⁷Cm | style="text-align:right" | 96 | style="text-align:right" | 141 | 237.05287(8) | >10# min | α (?%) | ²³³Pu | 5/2+# |-id=Curium-238 | rowspan=3|²³⁸Cm | rowspan=3 style="text-align:right" | 96 | rowspan=3 style="text-align:right" | 142 | rowspan=3|238.053082(13) | rowspan=3|Template:Val | EC? (96.11%) | ²³⁸Am | rowspan=3|0+ |- | α (3.84%) | ²³⁴Pu |- | SF (0.048%) | (various) |-id=Curium-239 | rowspan=2|²³⁹Cm | rowspan=2 style="text-align:right" | 96 | rowspan=2 style="text-align:right" | 143 | rowspan=2|239.05491(16) | rowspan=2|Template:Val | β⁺ | ²³⁹Am | rowspan=2|7/2−# |- | α (6.2x10⁻³%) | ²³⁵Pu |-id=Curium-240 | rowspan=2|²⁴⁰Cm | rowspan=2 style="text-align:right" | 96 | rowspan=2 style="text-align:right" | 144 | rowspan=2|240.0555282(20) | rowspan=2|Template:Val | α | ²³⁶Pu | rowspan=2|0+ |- | SF (3.9×10⁻⁶%) | (various) |-id=Curium-241 | rowspan=2|²⁴¹Cm | rowspan=2 style="text-align:right" | 96 | rowspan=2 style="text-align:right" | 145 | rowspan=2|241.0576512(17) | rowspan=2|Template:Val | EC (99.0%) | ²⁴¹Am | rowspan=2|1/2+ |- | α (1.0%) | ²³⁷Pu |-id=Curium-242 | rowspan=3|²⁴²Cm | rowspan=3 style="text-align:right" | 96 | rowspan=3 style="text-align:right" | 146 | rowspan=3|242.0588342(12) | rowspan=3|Template:Val | αTemplate:Refn | ²³⁸Pu | rowspan=3|0+ |- | SF (6.2×10⁻⁶%) | (various) |- | CD (1.1×10⁻¹⁴%) | ²⁰⁸Pb
³⁴Si |-id=Curium-242m | rowspan=2 style="text-indent:1em" | ^242mCm | rowspan=2 colspan="3" style="text-indent:2em" | 2800(100) keV | rowspan=2 | Template:Val | SF? | (various) | rowspan=2 | |- | IT? | ²⁴²Cm |-id=Curium-243 | rowspan=3|²⁴³Cm | rowspan=3 style="text-align:right" | 96 | rowspan=3 style="text-align:right" | 147 | rowspan=3|243.0613873(16) | rowspan=3|Template:Val | α (99.71%) | ²³⁹Pu | rowspan=3|5/2+ |- | EC (0.29%) | ²⁴³Am |- | SF (5.3×10⁻⁹%) | (various) |-id=Curium-243m | style="text-indent:1em" | ^243mCm | colspan="3" style="text-indent:2em" | 87.4(1) keV | Template:Val | IT | ²⁴³Cm | 1/2+ |-id=Curium-244 | rowspan=2|²⁴⁴Cm | rowspan=2 style="text-align:right" | 96 | rowspan=2 style="text-align:right" | 148 | rowspan=2|244.0627506(12) | rowspan=2|Template:Val | α | ²⁴⁰Pu | rowspan=2|0+ |- | SF (1.37×10⁻⁴%) | (various) |-id=Curium-244m1 | style="text-indent:1em" | ^244m1Cm | colspan="3" style="text-indent:2em" | 1040.181(11) keV | Template:Val | IT | ²⁴⁴Cm | 6+ |-id=Curium-244m2 | style="text-indent:1em" | ^244m2Cm | colspan="3" style="text-indent:2em" | 1100(900)# keV | >500 ns | SF | (various) | |-id=Curium-245 | rowspan=2|²⁴⁵Cm | rowspan=2 style="text-align:right" | 96 | rowspan=2 style="text-align:right" | 149 | rowspan=2|245.0654910(12) | rowspan=2|Template:Val | α | ²⁴¹Pu | rowspan=2|7/2+ |- | SF (6.1×10⁻⁷%) | (various) |-id=Curium-245m | style="text-indent:1em" | ^245mCm | colspan="3" style="text-indent:2em" | 355.92(10) keV | Template:Val | IT | ²⁴⁵Cm | 1/2+ |-id=Curium-246 | rowspan=2|²⁴⁶Cm | rowspan=2 style="text-align:right" | 96 | rowspan=2 style="text-align:right" | 150 | rowspan=2|246.0672220(16) | rowspan=2|Template:Val | α (99.97%) | ²⁴²Pu | rowspan=2|0+ |- | SF (0.02615%) | (various) |-id=Curium-246m | style="text-indent:1em" | ^246mCm | colspan="3" style="text-indent:2em" | 1179.66(13) keV | Template:Val | IT | ²⁴⁶Cm | 8− |-id=Curium-247 | ²⁴⁷Cm | style="text-align:right" | 96 | style="text-align:right" | 151 | 247.070353(4) | Template:Val | αTemplate:Refn | ²⁴³Pu | 9/2− |-id=Curium-247m1 | style="text-indent:1em" | ^247m1Cm | colspan="3" style="text-indent:2em" | 227.38(19) keV | Template:Val | IT | ²⁴⁷Cm | 5/2+ |-id=Curium-247m2 | style="text-indent:1em" | ^247m2Cm | colspan="3" style="text-indent:2em" | 404.90(3) keV | Template:Val | IT | ²⁴⁷Cm | 1/2+ |-id=Curium-248 | rowspan=2|²⁴⁸Cm | rowspan=2 style="text-align:right" | 96 | rowspan=2 style="text-align:right" | 152 | rowspan=2|248.0723491(25) | rowspan=2|Template:Val | α (91.61%)Template:Refn | ²⁴⁴Pu | rowspan=2|0+ |- | SF (8.39%) | (various) |-id=Curium-248m | style="text-indent:1em" | ^248mCm | colspan="3" style="text-indent:2em" | 1458.1(10) keV | Template:Val | IT | ²⁴⁸Cm | 8−# |-id=Curium-249 | ²⁴⁹Cm | style="text-align:right" | 96 | style="text-align:right" | 153 | 249.0759540(25) | Template:Val | β⁻ | ²⁴⁹Bk | 1/2+ |-id=Curium-249m | style="text-indent:1em" | ^249mCm | colspan="3" style="text-indent:2em" | 48.76(4) keV | Template:Val | | | 7/2+ |-id=Curium-250 | rowspan=3|²⁵⁰Cm | rowspan=3 style="text-align:right" | 96 | rowspan=3 style="text-align:right" | 154 | rowspan=3|250.078358(11) | rowspan=3|8300# yTemplate:Refn | SF | (various) | rowspan=3|0+ |- | α (?%) | ²⁴⁶Pu |- | β⁻ (?%) | ²⁵⁰Bk |-id=Curium-251 | ²⁵¹Cm | style="text-align:right" | 96 | style="text-align:right" | 155 | 251.082285(24) | Template:Val | β⁻ | ²⁵¹Bk | (3/2+) Template:Isotopes table/footer

References

• Isotope masses from:
  • Template:NUBASE 2003
• Half-life, spin, and isomer data selected from the following sources.
  • Template:NUBASE 2003
  • Template:NNDC
  • Template:CRC85