镅是人造元素，没有稳定同位素，也无法确认标准原子质量。目前已发现229Am至247Am（231Am除外）共18种同位素，以及未确认的223Am。其中，243Am最稳定，半衰期7350年。
Quick Facts 同位素, 衰变 ...
Close
More information 符号, Z ...
| 符号
|
Z
|
N
|
同位素质量（u）
[n 1][n 2]
|
半衰期
[n 2]
|
衰变
方式[1]
|
衰变
产物
|
原子核
自旋[n 1]
|
| 激发能量[n 1][n 2]
|
| 223Am[n 3]
|
95
|
128
|
223.04584(32)#
|
10(9) ms
|
α
|
219Np
|
9/2–#
|
| 229Am
|
95
|
134
|
229.04528(11)
|
1.8(15) s
|
α
|
225Np
|
5/2–#
|
| 230Am
|
95
|
135
|
230.04603(15)#
|
40(9) s
|
β+ (<70%)
|
230Pu
|
1–#
|
| β+, SF (>30%)
|
(various)
|
| 232Am
|
95
|
137
|
232.04659(32)#
|
79(2) s
|
β+ (98%)
|
232Pu
|
|
| α (2%)
|
228Np
|
| β+, SF (.069%)
|
(various)
|
| 233Am
|
95
|
138
|
233.04635(11)#
|
3.2(8) min
|
β+
|
233Pu
|
|
| α
|
229Np
|
| 234Am
|
95
|
139
|
234.04781(22)#
|
2.32(8) min
|
β+ (99.95%)
|
234Pu
|
|
| α (.04%)
|
230Np
|
| β+, SF (.0066%)
|
(various)
|
| 235Am
|
95
|
140
|
235.04795(13)#
|
9.9(5) min
|
β+
|
235Pu
|
5/2−#
|
| α （不常见）
|
231Np
|
| 236Am
|
95
|
141
|
236.04958(11)#
|
3.6(1) min
|
β+
|
236Pu
|
|
| α
|
232Np
|
| 237Am
|
95
|
142
|
237.05000(6)#
|
73.0(10) min
|
β+ (99.97%)
|
237Pu
|
5/2(−)
|
| α (.025%)
|
233Np
|
| 238Am
|
95
|
143
|
238.05198(5)
|
98(2) min
|
β+
|
238Pu
|
1+
|
| α (10−4%)
|
234Np
|
| 238mAm
|
2500(200)# keV
|
35(10) µs
|
|
|
|
| 239Am
|
95
|
144
|
239.0530245(26)
|
11.9(1) h
|
ε (99.99%)
|
239Pu
|
(5/2)−
|
| α (.01%)
|
235Np
|
| 239mAm
|
2500(200) keV
|
163(12) ns
|
|
|
(7/2+)
|
| 240Am
|
95
|
145
|
240.055300(15)
|
50.8(3) h
|
β+
|
240Pu
|
(3−)
|
| α (1.9×10−4%)
|
236Np
|
| 241Am[n 4]
|
95
|
146
|
241.0568291(20)
|
432.2(7) y
|
α
|
237Np
|
5/2−
|
| CD (7.4×10−10%)
|
207Tl, 34Si
|
| SF (4.3×10−10%)
|
(various)
|
| 241mAm
|
2200(100) keV
|
1.2(3) µs
|
|
|
|
| 242Am
|
95
|
147
|
242.0595492(20)
|
16.02(2) h
|
β− (82.7%)
|
242Cm
|
1−
|
| ε (17.3%)
|
242Pu
|
| 242m1Am
|
48.60(5) keV
|
141(2) y
|
IT (99.54%)
|
242Am
|
5−
|
| α (.46%)
|
238Np
|
| SF (1.5×10−8%)
|
(various)
|
| 242m2Am
|
2200(80) keV
|
14.0(10) ms
|
|
|
(2+,3−)
|
| 243Am[n 4]
|
95
|
148
|
243.0613811(25)
|
7,370(40) y
|
α
|
239Np
|
5/2−
|
| SF (3.7×10−9%)
|
(various)
|
| 244Am
|
95
|
149
|
244.0642848(22)
|
10.1(1) h
|
β−
|
244Cm
|
(6−)#
|
| 244mAm
|
86.1(10) keV
|
26(1) min
|
β− (99.96%)
|
244Cm
|
1+
|
| ε (.0361%)
|
244Pu
|
| 245Am
|
95
|
150
|
245.066452(4)
|
2.05(1) h
|
β−
|
245Cm
|
(5/2)+
|
| 246Am
|
95
|
151
|
246.069775(20)
|
39(3) min
|
β−
|
246Cm
|
(7−)
|
| 246m1Am
|
30(10) keV
|
25.0(2) min
|
β− (99.99%)
|
246Cm
|
2(−)
|
| IT (.01%)
|
246Am
|
| 246m2Am
|
~2000 keV
|
73(10) µs
|
|
|
|
| 247Am
|
95
|
152
|
247.07209(11)#
|
23.0(13) min
|
β−
|
247Cm
|
(5/2)#
|
Close
画上#号的数据代表没有经过实验的证明，仅为理论推测。
223Am的实验数据与理论预测相去甚远，因此其发现存疑。[2]
- 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.
