Het chemisch element promethium (Pm), met een atoommassa van ongeveer 146,92 u, bezit geen enkele stabiele isotoop. De 38 radio-isotopen zijn onstabiel en hebben een relatief korte halfwaardetijd (de meeste minder dan een seconde). Promethium is, na technetium, het tweede element in het periodiek systeem dat bijgevolg radioactief is. Het is een synthetisch element dat voor het eerst werd bereid in 1945.
De kortstlevende isotoop van promethium is 163Pm, met een halfwaardetijd van ongeveer 200 milliseconden. De langstlevende is 145Pm, met een halfwaardetijd van 17,7 jaar.
| Nuclide
|
Z (p)
|
N (n)
|
Isotopische massa (u)
|
Halveringstijd
|
Radioactief verval
|
VP
|
Kernspin
|
| Excitatie-energie
|
| 126Pm
|
61
|
65
|
125,95752(54)
|
0,5 s
|
|
|
|
| 127Pm
|
61
|
66
|
126,95163(64)
|
1 s
|
|
|
5/2+
|
| 128Pm
|
61
|
67
|
127,94842(43)
|
1,0(3) s
|
β+
|
128Nd
|
6+
|
| p
|
127Nd
|
| 129Pm
|
61
|
68
|
128,94316(43)
|
3 s [> 200 ns]
|
β+
|
129Nd
|
5/2+
|
| 130Pm
|
61
|
69
|
129,94045(32)
|
2,6(2) s
|
β+
|
130Nd
|
(5+, 6+, 4+)
|
| β+, p (zelden)
|
129Pr
|
| 131Pm
|
61
|
70
|
130,93587(21)
|
6,3(8) s
|
β+, p
|
130Pr
|
5/2+
|
| β+
|
131Nd
|
| 132Pm
|
61
|
71
|
131,93375(21)
|
6,2(6) s
|
β+
|
132Nd
|
(3+)
|
| β+, p (5 × 10−5%)
|
131Pr
|
| 133Pm
|
61
|
72
|
132,92978(5)
|
15(3) s
|
β+
|
133Nd
|
(3/2+)
|
| 133mPm
|
130,4(10) keV
|
10 s
|
β+
|
133Nd
|
(11/2−)
|
| IT
|
133Pm
|
| 134Pm
|
61
|
73
|
133,92835(6)
|
22(1) s
|
β+
|
134Nd
|
(5+)
|
| 134mPm
|
0(100) keV
|
± 5 s
|
IT
|
134Pm
|
(2+)
|
| 135Pm
|
61
|
74
|
134,92488(6)
|
49(3) s
|
β+
|
135Nd
|
(5/2+, 3/2+)
|
| 135mPm
|
50(100) keV
|
40(3) s
|
β+
|
135Nd
|
(11/2−)
|
| 136Pm
|
61
|
75
|
135,92357(8)
|
107(6) s
|
β+
|
136Nd
|
(5−)
|
| 136mPm
|
130(120) keV
|
47(2) s
|
β+
|
136Nd
|
(2+)
|
| 137Pm
|
61
|
76
|
136,920479(14)
|
2 min
|
β+
|
137Nd
|
5/2+
|
| 137mPm
|
150(50) keV
|
2,4(1) min
|
β+
|
137Nd
|
11/2−
|
| 138Pm
|
61
|
77
|
137,919548(30)
|
10(2) s
|
β+
|
138Nd
|
1+
|
| 138mPm
|
30(30) keV
|
3,24(5) min
|
β+
|
138Nd
|
5−
|
| 139Pm
|
61
|
78
|
138,916804(14)
|
4,15(5) min
|
β+
|
139Nd
|
5/2+
|
| 139mPm
|
188,7(3) keV
|
180(20) ms
|
IT (99,83%)
|
139Pm
|
11/2−
|
| β+ (0,17%)
|
139Nd
|
| 140Pm
|
61
|
79
|
139,91604(4)
|
9,2(2) s
|
β+
|
140Nd
|
1+
|
| 140mPm
|
420(40) keV
|
5,95(5) min
|
β+
|
140Nd
|
8−
|
| 141Pm
|
61
|
80
|
140,913555(15)
|
20,90(5) min
|
β+
|
141Nd
|
5/2+
|
| 141m1Pm
|
628,40(10) keV
|
630(20) ns
|
|
|
11/2−
|
| 141m2Pm
|
2530,9(5) keV
|
> 2 µs
|
|
|
|
| 142Pm
|
61
|
81
|
141,912874(27)
|
40,5(5) s
|
β+
|
142Nd
|
1+
|
| 142mPm
|
883,17(16) keV
|
2,0(2) ms
|
IT
|
142Pm
|
8−
|
| 143Pm
|
61
|
82
|
142,910933(4)
|
265(7) dagen
|
β+
|
143Nd
|
5/2+
|
| 144Pm
|
61
|
83
|
143,912591(3)
|
363(14) dagen
|
β+
|
144Nd
|
5−
|
| 144m1Pm
|
840,90(5) keV
|
780(200) ns
|
|
|
9+
|
| 144m2Pm
|
8595,8(22) keV
|
± 2,7 µs
|
|
|
(27+)
|
| 145Pm
|
61
|
84
|
144,912749(3)
|
17,7(4) jaar
|
EV
|
145Nd
|
5/2+
|
| α (2,8 × 10−7%)
|
141Pr
|
| 146Pm
|
61
|
85
|
145,914696(5)
|
5,53(5) jaar
|
EV (66%)
|
146Nd
|
3−
|
| β− (34%)
|
146Sm
|
| 147Pm
|
61
|
86
|
146,9151385(26)
|
2,6234(2) jaar
|
β−
|
147Sm
|
7/2+
|
| 148Pm
|
61
|
87
|
147,917475(7)
|
5,368(2) d
|
β−
|
148Sm
|
1−
|
| 148mPm
|
137,9(3) keV
|
41,29(11) dagen
|
β− (95%)
|
148Sm
|
5−, 6−
|
| IT (5%)
|
148Pm
|
| 149Pm
|
61
|
88
|
148,918334(4)
|
53,08(5) uur
|
β−
|
149Sm
|
7/2+
|
| 149mPm
|
240,214(7) keV
|
35(3) µs
|
|
|
11/2−
|
| 150Pm
|
61
|
89
|
149,920984(22)
|
2,68(2) uur
|
β−
|
150Sm
|
(1−)
|
| 151Pm
|
61
|
90
|
150,921207(6)
|
28,40(4) uur
|
β−
|
151Sm
|
5/2+
|
| 152Pm
|
61
|
91
|
151,923497(28)
|
4,12(8) min
|
β−
|
152Sm
|
1+
|
| 152m1Pm
|
140(90) keV
|
7,52(8) min
|
|
|
4−
|
| 152m2Pm
|
250(150) keV
|
13,8(2) min
|
|
|
(8)
|
| 153Pm
|
61
|
92
|
152,924117(12)
|
5,25(2) min
|
β−
|
153Sm
|
5/2−
|
| 154Pm
|
61
|
93
|
153,92646(5)
|
1,73(10) min
|
β−
|
154Sm
|
(0, 1)
|
| 154mPm
|
120(120) keV
|
2,68(7) min
|
β−
|
154Sm
|
(3, 4)
|
| 155Pm
|
61
|
94
|
154,92810(3)
|
41,5(2) s
|
β−
|
155Sm
|
(5/2−)
|
| 156Pm
|
61
|
95
|
155,93106(4)
|
26,70(10) s
|
β−
|
156Sm
|
4−
|
| 157Pm
|
61
|
96
|
156,93304(12)
|
10,56(10) s
|
β−
|
157Sm
|
(5/2−)
|
| 158Pm
|
61
|
97
|
157,93656(14)
|
4,8(5) s
|
β−
|
158Sm
|
|
| 159Pm
|
61
|
98
|
158,93897(21)
|
1,47(15) s
|
β−
|
159Sm
|
5/2−
|
| 160Pm
|
61
|
99
|
159,94299(32)
|
2 s
|
β−
|
160Sm
|
|
| 161Pm
|
61
|
100
|
160,94586(54)
|
700 ms
|
β−
|
161Sm
|
5/2−
|
| 162Pm
|
61
|
101
|
161,95029(75)
|
500 ms
|
β−
|
162Sm
|
|
| 163Pm
|
61
|
102
|
162,95368(86)
|
200 ms
|
β−
|
163Sm
|
5/2−
|
Overzicht van isotopen per element
bewerken
Bronnen, noten en/of referenties
- (en) R.B. Firestone, S.Y. Frank Chu & C.M. Baglin (1999) - Table of Isotopes (online versie van de cd-rom)
- (en) G. Audi, A.H. Wapstra, C. Thibault, J. Blachot & O. Bersillon (2003) - The NUBASE evaluation of nuclear and decay properties, Nuclear Physics A, 729, pp. 3-128
- (en) J.R. de Laeter, J.K. Böhlke, P. De Bièvre, H. Hidaka, H.S. Peiser, K.J.R. Rosman & P.D.P. Taylor (2003) - Atomic weights of the elements. Review 2000 (IUPAC Technical Report), Pure and Applied Chemistry, 75 (6), pp. 683–800
- (en) M.E. Wieser (2006) - Atomic weights of the elements 2005 (IUPAC Technical Report), Pure and Applied Chemistry, 78 (11), pp. 2051–2066
- (en) David R. Lide (2004) - CRC Handbook of Chemistry and Physics (85th ed.), hoofdstuk 11, CRC Press - ISBN 978-0849304859
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