鋦有從 233Cm 到 251Cm 共 19 種同位素以及 10 種同核異構體，全部都有放射性。其中，247Cm 最穩定，半衰期 1560 萬年，是之後所有原子序更高的核素半衰期的至少一萬倍。它是 R 過程產生的。鋦最穩定的同核異構體則是 246mCm，半衰期 112 秒。 圖表 rowspan2233Cm rowspan2 styletextalignright 96 rowspan2 styletextalignright 137 rowspan223305077 8 rowspan21 min 233Am rowspan232 229Pu rowspan2234Cm rowspan2 styletextalignright 96 rowspan2 styletextalignright 138 rowspan223405016 2 rowspan251 12 s 234Am rowspan20 230Pu rowspan2235Cm rowspan2 styletextalignright 96 rowspan2 styletextalignright 139 rowspan223505143 22 rowspan25 min 235Am rowspan252 231Pu rowspan2236Cm rowspan2 styletextalignright 96 rowspan2 styletextalignright 140 rowspan223605141 22 rowspan210 min 236Am rowspan20 232Pu rowspan2237Cm rowspan2 styletextalignright 96 rowspan2 styletextalignright 141 rowspan223705290 22 rowspan220 min 237Am rowspan252 233Pu rowspan2238Cm rowspan2 styletextalignright 96 rowspan2 styletextalignright 142 rowspan223805303 4 rowspan224 1 h 90 238Am rowspan20 10 234Pu rowspan2239Cm rowspan2 styletextalignright 96 rowspan2 styletextalignright 143 rowspan223905496 11 rowspan229 h 999 239Am rowspan272 1 235Pu rowspan3240Cm rowspan3 styletextalignright 96 rowspan3 styletextalignright 144 rowspan32400555295 25 rowspan327 1 d 995 236Pu rowspan30 5 240Am 39106 various rowspan2241Cm rowspan2 styletextalignright 96 rowspan2 styletextalignright 145 rowspan22410576530 23 rowspan2328 2 d 99 241Am rowspan212 1 237Pu rowspan3 242CmMost common isotopes rowspan3 styletextalignright 96 rowspan3 styletextalignright 146 rowspan3 2420588358 20 rowspan3 1628 2 d 238Pu rowspan3 0 SF 633106 various 1014 Heaviest known nuclide to undergo cluster decay 208Pb34Si rowspan3243Cm rowspan3 styletextalignright 96 rowspan3 styletextalignright 147 rowspan32430613891 22 rowspan3291 1 y 9971 239Pu rowspan352 29 243Am SF 53109 various styletextindent1em 243mCm colspan3 styletextindent2em 874 1 keV 108 3 µs 12 rowspan2244Cm rowspan2 styletextalignright 96 rowspan2 styletextalignright 148 rowspan22440627526 20 rowspan21810 2 y 240Pu rowspan20 SF 134104 various styletextindent1em 244mCm colspan3 styletextindent2em 1040188 12 keV 34 2 ms 244Cm 6 rowspan2245Cm rowspan2 styletextalignright 96 rowspan2 styletextalignright 149 rowspan22450654912 22 rowspan285 1103 y 241Pu rowspan272 SF 61107 various styletextindent1em 245mCm colspan3 styletextindent2em 35590 10 keV 290 20 ns 12 rowspan2246Cm rowspan2 styletextalignright 96 rowspan2 styletextalignright 150 rowspan22460672237 22 rowspan2476 4103 y 9997 242Pu rowspan20 SF 0261 various styletextindent1em 246mCm colspan3 styletextindent2em 117966 13 keV 112 024 s IT 246Cm 8 247Cm styletextalignright 96 styletextalignright 151 247070354 5 156 5107 y 243Pu 92 rowspan2 248Cm rowspan2 styletextalignright 96 rowspan2 styletextalignright 152 rowspan2 248072349 5 rowspan2 348 6105 y 9174 244Pu rowspan2 0 SF 826 various 249Cm styletextalignright 96 styletextalignright 153 249075953 5 6415 3 min 249Bk 12 styletextindent1em 249mCm colspan3 styletextindent2em 48758 17 keV 23 µs 72 rowspan3250Cm rowspan3 styletextalignright 96 rowspan3 styletextalignright 154 rowspan3250078357 12 rowspan38300 y SF 80 Lightest nuclide to undergo spontaneous fission as the main decay mode various rowspan30 11 246Pu 9 250Bk 251Cm styletextalignright 96 styletextalignright 155 251082285 24 168 2 min 251Bk 12 參考文獻 Isotope masses from Ame2003 Atomic Mass Evaluation by G Audi AH Wapstra C Thibault J Blachot and O Bersillon in Nuclear Physics A729 2003 Halflife spin and isomer data selected from these sources Editing notes on this articles talk page Audi Bersillon Blachot Wapstra The Nubase2003 evaluation of nuclear and decay properties Nuc Phys A 729 pp 3128 2003 National Nuclear Data Center Brookhaven National Laboratory Information extracted from the NuDat 21 database retrieved Sept 2005 David R Lide ed Norman E Holden in CRC Handbook of Chemistry and Physics 85th Edition online version CRC Press Boca Raton Florida 2005 Section 11 Table of the Isotopes Cm Category 鋦