錒的同位素
圖表

| 符號 | 歷史 名稱 | Z> 激發能量 | N> 激發能量 | 同位素質量（u） > 激發能量 | 半衰期 | 衰變方式 | 衰變產物 | 原子核 自旋 | 相對豐度 （莫耳分率） |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 204Ac |  | 89 | 115 |  | 6997740000000000000♠7.4+2.2 −1.4 ms | α | 200Fr |  |  |
| 205Ac |  | 89 | 116 |  | 6997770000000000000♠7.7+2.7 −1.6 ms | α | 201Fr | 9/2−? |  |
| 206Ac |  | 89 | 117 | 206.01450(8) | 25(7) ms | α | 202Fr | (3+) |  |
| 206m1Ac |  | 80(50) keV | 80(50) keV | 80(50) keV | 15(6) ms | α | 202Fr |  |  |
| 206m2Ac |  | 290(110)# keV | 290(110)# keV | 290(110)# keV | 41(16) ms | α | 202mFr | (10−) |  |
| 207Ac |  | 89 | 118 | 207.01195(6) | 31(8) ms [27(+11−6) ms] | α | 203Fr | 9/2−# |  |
| 208Ac |  | 89 | 119 | 208.01155(6) | 97(16) ms [95(+24−16) ms] | α (99%) | 204Fr | (3+) |  |
| 208Ac |  | 89 | 119 | 208.01155(6) | 97(16) ms [95(+24−16) ms] | β+ (1%) | 208Ra | (3+) |  |
| 208mAc |  | 506(26) keV | 506(26) keV | 506(26) keV | 28(7) ms [25(+9−5) ms] | α (89%) | 204Fr | (10−) |  |
| 208mAc |  | 506(26) keV | 506(26) keV | 506(26) keV | 28(7) ms [25(+9−5) ms] | IT (10%) | 208Ac | (10−) |  |
| 208mAc |  | 506(26) keV | 506(26) keV | 506(26) keV | 28(7) ms [25(+9−5) ms] | β+ (1%) | 208Ra | (10−) |  |
| 209Ac |  | 89 | 120 | 209.00949(5) | 92(11) ms | α (99%) | 205Fr | (9/2−) |  |
| 209Ac |  | 89 | 120 | 209.00949(5) | 92(11) ms | β+ (1%) | 209Ra | (9/2−) |  |
| 210Ac |  | 89 | 121 | 210.00944(6) | 350(40) ms | α (96%) | 206Fr | 7+# |  |
| 210Ac |  | 89 | 121 | 210.00944(6) | 350(40) ms | β+ (4%) | 210Ra | 7+# |  |
| 211Ac |  | 89 | 122 | 211.00773(8) | 213(25) ms | α (99.8%) | 207Fr | 9/2−# |  |
| 211Ac |  | 89 | 122 | 211.00773(8) | 213(25) ms | β+ (.2%) | 211Ra | 9/2−# |  |
| 212Ac |  | 89 | 123 | 212.00781(7) | 920(50) ms | α (97%) | 208Fr | 6+# |  |
| 212Ac |  | 89 | 123 | 212.00781(7) | 920(50) ms | β+ (3%) | 212Ra | 6+# |  |
| 213Ac |  | 89 | 124 | 213.00661(6) | 731(17) ms | α | 209Fr | (9/2−)# |  |
| 213Ac |  | 89 | 124 | 213.00661(6) | 731(17) ms | β+ （不常見） | 213Ra | (9/2−)# |  |
| 214Ac |  | 89 | 125 | 214.006902(24) | 8.2(2) s | α (89%) | 210Fr | (5+)# |  |
| 214Ac |  | 89 | 125 | 214.006902(24) | 8.2(2) s | β+ (11%) | 214Ra | (5+)# |  |
| 215Ac |  | 89 | 126 | 215.006454(23) | 0.17(1) s | α (99.91%) | 211Fr | 9/2− |  |
| 215Ac |  | 89 | 126 | 215.006454(23) | 0.17(1) s | β+ (.09%) | 215Ra | 9/2− |  |
| 216Ac |  | 89 | 127 | 216.008720(29) | 0.440(16) ms | α | 212Fr | (1−) |  |
| 216Ac |  | 89 | 127 | 216.008720(29) | 0.440(16) ms | β+ (7×10−5%) | 216Ra | (1−) |  |
| 216mAc |  | 44(7) keV | 44(7) keV | 44(7) keV | 443(7) µs |  |  | (9−) |  |
| 217Ac |  | 89 | 128 | 217.009347(14) | 69(4) ns | α (98%) | 213Fr | 9/2− |  |
| 217Ac |  | 89 | 128 | 217.009347(14) | 69(4) ns | β+ (2%) | 217Ra | 9/2− |  |
| 217mAc |  | 2012(20) keV | 2012(20) keV | 2012(20) keV | 740(40) ns |  |  | (29/2)+ |  |
| 218Ac |  | 89 | 129 | 218.01164(5) | 1.08(9) µs | α | 214Fr | (1−)# |  |
| 218mAc |  | 584(50)# keV | 584(50)# keV | 584(50)# keV | 103(11) ns |  |  | (11+) |  |
| 219Ac |  | 89 | 130 | 219.01242(5) | 11.8(15) µs | α | 215Fr | 9/2− |  |
| 219Ac |  | 89 | 130 | 219.01242(5) | 11.8(15) µs | β+ (10−6%) | 219Ra | 9/2− |  |
| 220Ac |  | 89 | 131 | 220.014763(16) | 26.36(19) ms | α | 216Fr | (3−) |  |
| 220Ac |  | 89 | 131 | 220.014763(16) | 26.36(19) ms | β+ (5×10−4%) | 220Ra | (3−) |  |
| 221Ac |  | 89 | 132 | 221.01559(5) | 52(2) ms | α | 217Fr | 9/2−# |  |
| 222Ac |  | 89 | 133 | 222.017844(6) | 5.0(5) s | α (99%) | 218Fr | 1− |  |
| 222Ac |  | 89 | 133 | 222.017844(6) | 5.0(5) s | β+ (1%) | 222Ra | 1− |  |
| 222mAc |  | 200(150)# keV | 200(150)# keV | 200(150)# keV | 1.05(7) min | α (88.6%) | 218Fr | high |  |
| 222mAc |  | 200(150)# keV | 200(150)# keV | 200(150)# keV | 1.05(7) min | IT (10%) | 222Ac | high |  |
| 222mAc |  | 200(150)# keV | 200(150)# keV | 200(150)# keV | 1.05(7) min | β+ (1.4%) | 222Ra | high |  |
| 223Ac |  | 89 | 134 | 223.019137(8) | 2.10(5) min | α (99%) | 219Fr | (5/2−) |  |
| 223Ac |  | 89 | 134 | 223.019137(8) | 2.10(5) min | ε (1%) | 223Ra | (5/2−) |  |
| 223Ac |  | 89 | 134 | 223.019137(8) | 2.10(5) min | CD (3.2×10−9%) | 209Bi 14C | (5/2−) |  |
| 224Ac |  | 89 | 135 | 224.021723(4) | 2.78(17) h | β+ (90.9%) | 224Ra | 0− |  |
| 224Ac |  | 89 | 135 | 224.021723(4) | 2.78(17) h | α (9.1%) | 220Fr | 0− |  |
| 224Ac |  | 89 | 135 | 224.021723(4) | 2.78(17) h | β− (1.6%) | 224Th | 0− |  |
| 225Ac |  | 89 | 136 | 225.023230(5) | 10.0(1) d | α | 221Fr | (3/2−) |  |
| 225Ac |  | 89 | 136 | 225.023230(5) | 10.0(1) d | CD (6×10−10%) | 211 Bi  14C | (3/2−) |  |
| 226Ac |  | 89 | 137 | 226.026098(4) | 29.37(12) h | β− (83%) | 226Th | (1)(−#) |  |
| 226Ac |  | 89 | 137 | 226.026098(4) | 29.37(12) h | ε (17%) | 226Ra | (1)(−#) |  |
| 226Ac |  | 89 | 137 | 226.026098(4) | 29.37(12) h | α (.006%) | 222Fr | (1)(−#) |  |
| 227Ac | Actinium | 89 | 138 | 227.0277521(26) | 21.772(3) y | β− (98.61%) | 227Th | 3/2− | Trace |
| 227Ac | Actinium | 89 | 138 | 227.0277521(26) | 21.772(3) y | α (1.38%) | 223Fr | 3/2− | Trace |
| 228Ac | Mesothorium 2 | 89 | 139 | 228.0310211(27) | 6.13(2) h | β− | 228Th | 3+ | Trace |
| 229Ac |  | 89 | 140 | 229.03302(4) | 62.7(5) min | β− | 229Th | (3/2+) |  |
| 230Ac |  | 89 | 141 | 230.03629(32) | 122(3) s | β− | 230Th | (1+) |  |
| 231Ac |  | 89 | 142 | 231.03856(11) | 7.5(1) min | β− | 231Th | (1/2+) |  |
| 232Ac |  | 89 | 143 | 232.04203(11) | 119(5) s | β− | 232Th | (1+) |  |
| 233Ac |  | 89 | 144 | 233.04455(32)# | 145(10) s | β− | 233Th | (1/2+) |  |
| 234Ac |  | 89 | 145 | 234.04842(43)# | 44(7) s | β− | 234Th |  |  |
| 235Ac |  | 89 | 146 | 235.05123(38)# | 40# s | β− | 235Th | 1/2+# |  |
| 236Ac |  | 89 | 147 | 236.05530(54)# | 2# min | β− | 236Th |  |  |
1 2 3 4  畫上#號的數據代表沒有經過實驗的証明，僅為理論推測。
1 2 3  用括號括起來的數據代表不確定性。
↑  半衰期超过5亿年的衰变产物以粗斜体表示。
↑  Has medical uses
↑  Source of element's name
↑  Intermediate decay product of 235U
↑  Intermediate decay product of 232Th
| 0 | 1 | 2 |
| --- | --- | --- |

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