錒沒有穩定同位素。它最穩定的同位素是半衰期 21772 年的 227Ac。 圖表 204Ac styletextalignright 89 styletextalignright 115 α 200Fr 205Ac styletextalignright 89 styletextalignright 116 α 201Fr 92 206Ac styletextalignright 89 styletextalignright 117 20601450 8 25 7 ms α 202Fr 3 styletextindent1em 206m1Ac colspan3 styletextindent2em 80 50 keV 15 6 ms α 202Fr styletextindent1em 206m2Ac colspan3 styletextindent2em 290 110 keV 41 16 ms α 202mFr 10 207Ac styletextalignright 89 styletextalignright 118 20701195 6 31 8 ms 27 116 ms 203Fr 92 rowspan2208Ac rowspan2 rowspan2 styletextalignright 89 rowspan2 styletextalignright 119 rowspan220801155 6 rowspan297 16 ms 95 2416 ms 99 204Fr rowspan23 rowspan2 1 208Ra rowspan3 styletextindent1em 208mAc rowspan3 rowspan3 colspan3 styletextindent2em 506 26 keV rowspan328 7 ms 25 95 ms 89 204Fr rowspan310 rowspan3 IT 10 208Ac 1 208Ra rowspan2209Ac rowspan2 rowspan2 styletextalignright 89 rowspan2 styletextalignright 120 rowspan220900949 5 rowspan292 11 ms 99 205Fr rowspan292 rowspan2 1 209Ra rowspan2210Ac rowspan2 rowspan2 styletextalignright 89 rowspan2 styletextalignright 121 rowspan221000944 6 rowspan2350 40 ms 96 206Fr rowspan27 rowspan2 4 210Ra rowspan2211Ac rowspan2 rowspan2 styletextalignright 89 rowspan2 styletextalignright 122 rowspan221100773 8 rowspan2213 25 ms 998 207Fr rowspan292 rowspan2 2 211Ra rowspan2212Ac rowspan2 rowspan2 styletextalignright 89 rowspan2 styletextalignright 123 rowspan221200781 7 rowspan2920 50 ms 97 208Fr rowspan26 rowspan2 3 212Ra rowspan2213Ac rowspan2 rowspan2 styletextalignright 89 rowspan2 styletextalignright 124 rowspan221300661 6 rowspan2731 17 ms 209Fr rowspan292 rowspan2 （不常見） 213Ra rowspan2214Ac rowspan2 rowspan2 styletextalignright 89 rowspan2 styletextalignright 125 rowspan2214006902 24 rowspan282 2 s 89 210Fr rowspan25 rowspan2 11 214Ra rowspan2215Ac rowspan2 rowspan2 styletextalignright 89 rowspan2 styletextalignright 126 rowspan2215006454 23 rowspan2017 1 s 9991 211Fr rowspan292 rowspan2 09 215Ra rowspan2216Ac rowspan2 rowspan2 styletextalignright 89 rowspan2 styletextalignright 127 rowspan2216008720 29 rowspan20440 16 ms 212Fr rowspan21 rowspan2 7105 216Ra styletextindent1em 216mAc colspan3 styletextindent2em 44 7 keV 443 7 µs 9 rowspan2217Ac rowspan2 rowspan2 styletextalignright 89 rowspan2 styletextalignright 128 rowspan2217009347 14 rowspan269 4 ns 98 213Fr rowspan292 rowspan2 2 217Ra styletextindent1em 217mAc colspan3 styletextindent2em 2012 20 keV 740 40 ns 292 218Ac styletextalignright 89 styletextalignright 129 21801164 5 108 9 µs 214Fr 1 styletextindent1em 218mAc colspan3 styletextindent2em 584 50 keV 103 11 ns 11 rowspan2219Ac rowspan2 rowspan2 styletextalignright 89 rowspan2 styletextalignright 130 rowspan221901242 5 rowspan2118 15 µs 215Fr rowspan292 rowspan2 106 219Ra rowspan2220Ac rowspan2 rowspan2 styletextalignright 89 rowspan2 styletextalignright 131 rowspan2220014763 16 rowspan22636 19 ms 216Fr rowspan23 rowspan2 5104 220Ra 221Ac styletextalignright 89 styletextalignright 132 22101559 5 52 2 ms 217Fr 92 rowspan2222Ac rowspan2 rowspan2 styletextalignright 89 rowspan2 styletextalignright 133 rowspan2222017844 6 rowspan250 5 s 99 218Fr rowspan21 rowspan2 1 222Ra rowspan3 styletextindent1em 222mAc rowspan3 rowspan3 colspan3 styletextindent2em 200 150 keV rowspan3105 7 min 886 218Fr rowspan3high rowspan3 IT 10 222Ac 14 222Ra rowspan3223Ac rowspan3 rowspan3 styletextalignright 89 rowspan3 styletextalignright 134 rowspan3223019137 8 rowspan3210 5 min 99 219Fr rowspan352 rowspan3 1 223Ra 32109 rowspan3224Ac rowspan3 rowspan3 styletextalignright 89 rowspan3 styletextalignright 135 rowspan3224021723 4 rowspan3278 17 h 909 224Ra rowspan30 rowspan3 91 220Fr 16 224Th rowspan2225AcHas medical uses rowspan2 rowspan2 styletextalignright 89 rowspan2 styletextalignright 136 rowspan2225023230 5 rowspan2100 1 d 221Fr rowspan232 rowspan2 61010 rowspan3226Ac rowspan3 rowspan3 styletextalignright 89 rowspan3 styletextalignright 137 rowspan3226026098 4 rowspan32937 12 h 83 226Th rowspan31 rowspan3 17 226Ra 006 222Fr rowspan2227Ac rowspan2ActiniumSource of elements name rowspan2 styletextalignright 89 rowspan2 styletextalignright 138 rowspan22270277521 26 rowspan221772 3 y 9861 227Th rowspan232 rowspan2TraceIntermediate decay product of 235U 138 223Fr 228Ac Mesothorium 2 styletextalignright 89 styletextalignright 139 2280310211 27 613 2 h 228Th 3 TraceIntermediate decay product of 232Th 229Ac styletextalignright 89 styletextalignright 140 22903302 4 627 5 min 229Th 32 230Ac styletextalignright 89 styletextalignright 141 23003629 32 122 3 s 230Th 1 231Ac styletextalignright 89 styletextalignright 142 23103856 11 75 1 min 231Th 12 232Ac styletextalignright 89 styletextalignright 143 23204203 11 119 5 s 232Th 1 233Ac styletextalignright 89 styletextalignright 144 23304455 32 145 10 s 233Th 12 234Ac styletextalignright 89 styletextalignright 145 23404842 43 44 7 s 234Th 235Ac styletextalignright 89 styletextalignright 146 23505123 38 40 s 235Th 12 236Ac styletextalignright 89 styletextalignright 147 23605530 54 2 min 236Th 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 Ac Category 錒