镎的同位素
镎只痕量存在于自然界，通常由人工合成制得，因此无法确定标准原子量。镎有从219Np至244Np（不包括221Np）共25种同位素，没有一个是稳定的。最长寿的放射性同位素是237Np，半衰期214.4万年。[1]
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图表
| 符号 | Z | N | 同位素质量（u） [n 1][n 2] |
半衰期 [n 1][n 2] |
衰变 方式[2] |
衰变 产物 [n 3] |
原子核 自旋[n 1] |
相对丰度 （莫耳分率） |
|---|---|---|---|---|---|---|---|---|
| 激发能量[n 1][n 2] | ||||||||
| 225 Np |
93 | 132 | 225.03391(8) | 3# ms [>2 µs] | α | 221Pa | 9/2−# | |
| 226 Np |
93 | 133 | 226.03515(10)# | 35(10) ms | α | 222Pa | ||
| 227 Np |
93 | 134 | 227.03496(8) | 510(60) ms | α (99.95%) | 223Pa | 5/2−# | |
| β+ (.05%) | 227U | |||||||
| 228 Np |
93 | 135 | 228.03618(21)# | 61.4(14) s | β+ (59%) | 228U | ||
| α (41%) | 224Pa | |||||||
| β+, SF (.012%) | (various) | |||||||
| 229 Np |
93 | 136 | 229.03626(9) | 4.0(2) min | α (51%) | 225Pa | 5/2+# | |
| β+ (49%) | 229U | |||||||
| 230 Np |
93 | 137 | 230.03783(6) | 4.6(3) min | β+ (97%) | 230U | ||
| α (3%) | 226Pa | |||||||
| 231 Np |
93 | 138 | 231.03825(5) | 48.8(2) min | β+ (98%) | 231U | (5/2)(+#) | |
| α (2%) | 227Pa | |||||||
| 232 Np |
93 | 139 | 232.04011(11)# | 14.7(3) min | β+ (99.99%) | 232U | (4+) | |
| α (.003%) | 228Pa | |||||||
| 233 Np |
93 | 140 | 233.04074(5) | 36.2(1) min | β+ (99.99%) | 233U | (5/2+) | |
| α (.001%) | 229Pa | |||||||
| 234 Np |
93 | 141 | 234.042895(9) | 4.4(1) d | β+ | 234U | (0+) | |
| 235 Np |
93 | 142 | 235.0440633(21) | 396.1(12) d | ε | 235U | 5/2+ | |
| α (.0026%) | 231Pa | |||||||
| 236 Np [n 4] |
93 | 143 | 236.04657(5) | 1.54(6)×105 y | ε (87.3%) | 236U | (6−) | |
| β− (12.5%) | 236Pu | |||||||
| α (.16%) | 232Pa | |||||||
| 236m Np |
60(50) keV | 22.5(4) h | ε (52%) | 236U | 1 | |||
| β− (48%) | 236Pu | |||||||
| 237 Np [n 4][n 5] |
93 | 144 | 237.0481734(20) | 2.144(7)×106 y | α | 233Pa | 5/2+ | 痕量[n 6] |
| SF (2×10−10%) | (various) | |||||||
| CD (4×10−12%) | 207Tl 30Mg | |||||||
| 238 Np |
93 | 145 | 238.0509464(20) | 2.117(2) d | β− | 238Pu | 2+ | |
| 238m Np |
2300(200)# keV | 112(39) ns | ||||||
| 239 Np |
93 | 146 | 239.0529390(22) | 2.356(3) d | β− | 239Pu | 5/2+ | 痕量[n 6] |
| 240 Np |
93 | 147 | 240.056162(16) | 61.9(2) min | β− | 240Pu | (5+) | 痕量[n 7] |
| 240m Np |
20(15) keV | 7.22(2) min | β− (99.89%) | 240Pu | 1(+) | |||
| IT (.11%) | 240Np | |||||||
| 241 Np |
93 | 148 | 241.05825(8) | 13.9(2) min | β− | 241Pu | (5/2+) | |
| 242 Np |
93 | 149 | 242.06164(21) | 2.2(2) min | β− | 242Pu | (1+) | |
| 242m Np |
0(50)# keV | 5.5(1) min | 6+# | |||||
| 243 Np |
93 | 150 | 243.06428(3)# | 1.85(15) min | β− | 243Pu | (5/2−) | |
| 244 Np |
93 | 151 | 244.06785(32)# | 2.29(16) min | β− | 244Pu | (7−) | |
- ^ 1.0 1.1 1.2 1.3 画上#号的数据代表没有经过实验的证明，仅为理论推测。
- ^ 2.0 2.1 2.2 用括号括起来的数据代表不确定性。
- ^ 半衰期超过5亿年的衰变产物以粗斜体表示。
- ^ 4.0 4.1 Fissile nuclide
- ^ 最常见同位素
- ^ 6.0 6.1 由铀的中子捕获产生
- ^ 244Pu的衰变产物
| ← | 同位素列表 | → |
| 铀的同位素 | 镎的同位素 | 钚的同位素 |
参考文献
- ^ Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. The NUBASE2020 evaluation of nuclear properties (PDF). Chinese Physics C. 2021, 45 (3): 030001. doi:10.1088/1674-1137/abddae.
- ^ Universal Nuclide Chart
. nucleonica. [2015-11-03]. （原始内容存档于2017-02-19）.
- Isotope masses from Ame2003 Atomic Mass Evaluation by G. Audi, A.H. Wapstra, C. Thibault, J. Blachot and O. Bersillon in Nuclear Physics A729 (2003).
- Half-life, spin, and isomer data selected from these sources. Editing notes on this article's talk page.
- Audi, Bersillon, Blachot, Wapstra. The Nubase2003 evaluation of nuclear and decay properties （页面存档备份，存于互联网档案馆）, Nuc. Phys. A 729, pp. 3-128 (2003).
- National Nuclear Data Center, Brookhaven National Laboratory. Information extracted from the NuDat 2.1 database （页面存档备份，存于互联网档案馆） (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.