Isotopes of curium

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 isomer is 246mCm with a half-life of 1.12 seconds.

List of isotopes

 * rowspan=2|233Cm
 * rowspan=2 style="text-align:right" | 96
 * rowspan=2 style="text-align:right" | 137
 * rowspan=2|233.05077(8)
 * rowspan=2|$23 s$
 * β+ (80%)
 * 233Am
 * rowspan=2|3/2+#
 * α (20%)
 * 229Pu
 * rowspan=3|234Cm
 * rowspan=3 style="text-align:right" | 96
 * rowspan=3 style="text-align:right" | 138
 * rowspan=3|234.05016(2)
 * rowspan=3|52(9) s
 * β+ (71%)
 * 234Am
 * rowspan=3|0+
 * α (27%)
 * 230Pu
 * SF (2%)
 * (various)
 * rowspan=2|235Cm
 * rowspan=2 style="text-align:right" | 96
 * rowspan=2 style="text-align:right" | 139
 * rowspan=2|235.05143(22)#
 * rowspan=2|$300 s$
 * β+ (99.0%)
 * 235Am
 * rowspan=2|(5/2+)
 * α (1.0%)
 * 231Pu
 * rowspan=3|236Cm
 * rowspan=3 style="text-align:right" | 96
 * rowspan=3 style="text-align:right" | 140
 * rowspan=3|236.05141(22)#
 * rowspan=3|6.8(8) min
 * β+ (82%)
 * 236Am
 * rowspan=3|0+
 * α (18%)
 * 232Pu
 * SF (<0.1%)
 * (various)
 * rowspan=2|237Cm
 * rowspan=2 style="text-align:right" | 96
 * rowspan=2 style="text-align:right" | 141
 * rowspan=2|237.05290(22)#
 * rowspan=2|>660 s
 * β+
 * 237Am
 * rowspan=2|(5/2+)
 * α (<1%)
 * 233Pu
 * rowspan=2|238Cm
 * rowspan=2 style="text-align:right" | 96
 * rowspan=2 style="text-align:right" | 142
 * rowspan=2|238.05303(4)
 * rowspan=2|2.2(4) h
 * EC (~94%)
 * 238Am
 * rowspan=2|0+
 * α (~6%)
 * 234Pu
 * rowspan=2|239Cm
 * rowspan=2 style="text-align:right" | 96
 * rowspan=2 style="text-align:right" | 143
 * rowspan=2|239.05496(11)#
 * rowspan=2|2.5(4) h
 * β+
 * 239Am
 * rowspan=2|(7/2−)
 * α (6.2x10−3%)
 * 235Pu
 * rowspan=3|240Cm
 * rowspan=3 style="text-align:right" | 96
 * rowspan=3 style="text-align:right" | 144
 * rowspan=3|240.0555295(25)
 * rowspan=3|27(1) d
 * α (99.5%)
 * 236Pu
 * rowspan=3|0+
 * EC (.5%)
 * 240Am
 * SF (3.9×10−6%)
 * (various)
 * rowspan=2|241Cm
 * rowspan=2 style="text-align:right" | 96
 * rowspan=2 style="text-align:right" | 145
 * rowspan=2|241.0576530(23)
 * rowspan=2|32.8(2) d
 * EC (99%)
 * 241Am
 * rowspan=2|1/2+
 * α (1%)
 * 237Pu
 * rowspan=3|242Cm
 * rowspan=3 style="text-align:right" | 96
 * rowspan=3 style="text-align:right" | 146
 * rowspan=3|242.0588358(20)
 * rowspan=3|162.8(2) d
 * α
 * 238Pu
 * rowspan=3|0+
 * SF (6.33×10−6%)
 * (various)
 * CD (10−14%)
 * 208Pb 34Si
 * style="text-indent:1em" | 242mCm
 * colspan="3" style="text-indent:2em" | 2800(100) keV
 * 180(70) ns
 * rowspan=3|243Cm
 * rowspan=3 style="text-align:right" | 96
 * rowspan=3 style="text-align:right" | 147
 * rowspan=3|243.0613891(22)
 * rowspan=3|29.1(1) y
 * α (99.71%)
 * 239Pu
 * rowspan=3|5/2+
 * EC (.29%)
 * 243Am
 * SF (5.3×10−9%)
 * (various)
 * style="text-indent:1em" | 243mCm
 * colspan="3" style="text-indent:2em" | 87.4(1) keV
 * 1.08(3) μs
 * IT
 * 243Cm
 * 1/2+
 * rowspan=2|244Cm
 * rowspan=2 style="text-align:right" | 96
 * rowspan=2 style="text-align:right" | 148
 * rowspan=2|244.0627526(20)
 * rowspan=2|18.10(2) y
 * α
 * 240Pu
 * rowspan=2|0+
 * SF (1.34×10−4%)
 * (various)
 * style="text-indent:1em" | 244m1Cm
 * colspan="3" style="text-indent:2em" | 1040.188(12) keV
 * 34(2) ms
 * IT
 * 244Cm
 * 6+
 * style="text-indent:1em" | 244m2Cm
 * colspan="3" style="text-indent:2em" | 1100(900)# keV
 * >500 ns
 * SF
 * (various)
 * rowspan=2|245Cm
 * rowspan=2 style="text-align:right" | 96
 * rowspan=2 style="text-align:right" | 149
 * rowspan=2|245.0654912(22)
 * rowspan=2|8.5(1)×103 y
 * α
 * 241Pu
 * rowspan=2|7/2+
 * SF (6.1×10−7%)
 * (various)
 * style="text-indent:1em" | 245mCm
 * colspan="3" style="text-indent:2em" | 355.92(10) keV
 * 290(20) ns
 * IT
 * 245Cm
 * 1/2+
 * rowspan=2|246Cm
 * rowspan=2 style="text-align:right" | 96
 * rowspan=2 style="text-align:right" | 150
 * rowspan=2|246.0672237(22)
 * rowspan=2|4.76(4)×103 y
 * α (99.97%)
 * 242Pu
 * rowspan=2|0+
 * SF (.0261%)
 * (various)
 * style="text-indent:1em" | 246mCm
 * colspan="3" style="text-indent:2em" | 1179.66(13) keV
 * 1.12(0.24) s
 * IT
 * 246Cm
 * 8−
 * 247Cm
 * style="text-align:right" | 96
 * style="text-align:right" | 151
 * 247.070354(5)
 * 1.56(5)×107 y
 * α
 * 243Pu
 * 9/2−
 * style="text-indent:1em" | 247m1Cm
 * colspan="3" style="text-indent:2em" | 227.38(19) keV
 * 26.3(0.3) μs
 * IT
 * 247Cm
 * 5/2+
 * style="text-indent:1em" | 247m2Cm
 * colspan="3" style="text-indent:2em" | 404.90(3) keV
 * 100.6(0.6) ns
 * IT
 * 247Cm
 * 1/2+
 * rowspan=2|248Cm
 * rowspan=2 style="text-align:right" | 96
 * rowspan=2 style="text-align:right" | 152
 * rowspan=2|248.072349(5)
 * rowspan=2|3.48(6)×105 y
 * α (91.74%)
 * 244Pu
 * rowspan=2|0+
 * SF (8.26%)
 * (various)
 * style="text-indent:1em" | 248mCm
 * colspan="3" style="text-indent:2em" | 1458.1(1) keV
 * 146(18) μs
 * IT
 * 248Cm
 * (8−)
 * 249Cm
 * style="text-align:right" | 96
 * style="text-align:right" | 153
 * 249.075953(5)
 * 64.15(3) min
 * β−
 * 249Bk
 * 1/2(+)
 * style="text-indent:1em" | 249mCm
 * colspan="3" style="text-indent:2em" | 48.758(17) keV
 * 23 μs
 * α
 * 245Pu
 * (7/2+)
 * rowspan=3|250Cm
 * rowspan=3 style="text-align:right" | 96
 * rowspan=3 style="text-align:right" | 154
 * rowspan=3|250.078357(12)
 * rowspan=3|8300# y
 * SF (74%)
 * (various)
 * rowspan=3|0+
 * α (18%)
 * 246Pu
 * β− (8%)
 * 250Bk
 * 251Cm
 * style="text-align:right" | 96
 * style="text-align:right" | 155
 * 251.082285(24)
 * 16.8(2) min
 * β−
 * 251Bk
 * (1/2+)
 * rowspan=2|248.072349(5)
 * rowspan=2|3.48(6)×105 y
 * α (91.74%)
 * 244Pu
 * rowspan=2|0+
 * SF (8.26%)
 * (various)
 * style="text-indent:1em" | 248mCm
 * colspan="3" style="text-indent:2em" | 1458.1(1) keV
 * 146(18) μs
 * IT
 * 248Cm
 * (8−)
 * 249Cm
 * style="text-align:right" | 96
 * style="text-align:right" | 153
 * 249.075953(5)
 * 64.15(3) min
 * β−
 * 249Bk
 * 1/2(+)
 * style="text-indent:1em" | 249mCm
 * colspan="3" style="text-indent:2em" | 48.758(17) keV
 * 23 μs
 * α
 * 245Pu
 * (7/2+)
 * rowspan=3|250Cm
 * rowspan=3 style="text-align:right" | 96
 * rowspan=3 style="text-align:right" | 154
 * rowspan=3|250.078357(12)
 * rowspan=3|8300# y
 * SF (74%)
 * (various)
 * rowspan=3|0+
 * α (18%)
 * 246Pu
 * β− (8%)
 * 250Bk
 * 251Cm
 * style="text-align:right" | 96
 * style="text-align:right" | 155
 * 251.082285(24)
 * 16.8(2) min
 * β−
 * 251Bk
 * (1/2+)
 * 251Cm
 * style="text-align:right" | 96
 * style="text-align:right" | 155
 * 251.082285(24)
 * 16.8(2) min
 * β−
 * 251Bk
 * (1/2+)