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 编辑
符号 | Z( p ) |
N( n ) |
同位素质量(u) | 半衰期 | 衰变 方式[2][n 1] |
衰变 产物 |
原子核 自旋 |
---|---|---|---|---|---|---|---|
激发能量 | |||||||
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 2] |
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 2][n 3] |
93 | 144 | 237.0481734(20) | 2.144(7)×106 y | α | 233Pa | 5/2+ |
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+ |
240 Np |
93 | 147 | 240.056162(16) | 61.9(2) min | β− | 240Pu | (5+) |
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−) |
备注:画上#号的数据代表没有经过实验的证明,只是理论推测而已,而用括号括起来的代表数据不确定性。
← | 同位素列表 | → |
铀的同位素 | 镎的同位素 | 钚的同位素 |
注释 编辑
- ^ Abbreviations:
CD: Cluster decay
EC: Electron capture
IT: Isomeric transition
SF: Spontaneous fission - ^ 2.0 2.1 Fissile nuclide
- ^ Most common nuclide
参考文献 编辑
- ^ 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.