Isotopes of neodymium

Naturally occurring neodymium (Nd) is composed of 5 stable isotopes, 142Nd, 143Nd, 145Nd, 146Nd and 148Nd, with 142Nd being the most abundant (27.2% natural abundance), and 2 radioisotopes, 144Nd and 150Nd. In all, 31 radioisotopes of Neodymium have been characterized up to now, with the most stable being naturally occurring isotopes 144Nd (alpha decay, a half-life (T½) of 2.29×1015 years) and 150Nd (double beta decay, T½ of 7×1018 years). All of the remaining radioactive isotopes have half-lives that are less than 11 days, and the majority of these have half-lives that are less than 70 seconds. This element also has 13 known meta states with the most stable being 139mNd (T½ 5.5 hours), 135mNd (T½ 5.5 minutes) and 133m1Nd (T½ ~70 seconds).

The primary decay modes before the most abundant stable isotope, 142Nd, are electron capture and positron decay, and the primary mode after is beta minus decay. The primary decay products before 142Nd are element Pr (praseodymium) isotopes and the primary products after are element Pm (promethium) isotopes.
Standard atomic mass: 144.242(3) u

## Table

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nuclide
symbol  | Z(p)  | N(n)  |
isotopic mass (u)
| half-life  | nuclear
spin  | representative
isotopic
composition
(mole fraction)  | range of natural
variation
(mole fraction)

|
|
|
|
|
|
|

excitation energy
124Nd  | 60  | 64  | 123.95223(64)#  | 500# ms  | 0+  |  |
125Nd  | 60  | 65  | 124.94888(43)#  | 600(150) ms  | 5/2(+#)  |  |
126Nd  | 60  | 66  | 125.94322(43)#  | 1# s [>200 ns]  | 0+  |  |
127Nd  | 60  | 67  | 126.94050(43)#  | 1.8(4) s  | 5/2+#  |  |
128Nd  | 60  | 68  | 127.93539(21)#  | 5# s  | 0+  |  |
129Nd  | 60  | 69  | 128.93319(22)#  | 4.9(2) s  | 5/2+#  |  |
130Nd  | 60  | 70  | 129.92851(3)  | 21(3) s  | 0+  |  |
131Nd  | 60  | 71  | 130.92725(3)  | 33(3) s  | (5/2)(+#)  |  |
132Nd  | 60  | 72  | 131.923321(26)  | 1.56(10) min  | 0+  |  |
133Nd  | 60  | 73  | 132.92235(5)  | 70(10) s  | (7/2+)  |  |
133m1Nd  | 127.97(11) keV  | ~70 s  | (1/2)+  |  |
133m2Nd  | 176.10(10) keV  | ~300 ns  | (9/2-)  |  |
134Nd  | 60  | 74  | 133.918790(13)  | 8.5(15) min  | 0+  |  |
134mNd  | 2293.1(4) keV  | 410(30) µs  | (8)-  |  |
135Nd  | 60  | 75  | 134.918181(21)  | 12.4(6) min  | 9/2(-)  |  |
135mNd  | 65.0(2) keV  | 5.5(5) min  | (1/2+)  |  |
136Nd  | 60  | 76  | 135.914976(13)  | 50.65(33) min  | 0+  |  |
137Nd  | 60  | 77  | 136.914567(12)  | 38.5(15) min  | 1/2+  |  |
137mNd  | 519.43(17) keV  | 1.60(15) s  | (11/2-)  |  |
138Nd  | 60  | 78  | 137.911950(13)  | 5.04(9) h  | 0+  |  |
138mNd  | 3174.9(4) keV  | 410(50) ns  | (10+)  |  |
139Nd  | 60  | 79  | 138.911978(28)  | 29.7(5) min  | 3/2+  |  |
139m1Nd  | 231.15(5) keV  | 5.50(20) h  | 11/2-  |  |
139m2Nd  | 2570.9+X keV  | >=141 ns  |  |  |
140Nd  | 60  | 80  | 139.90955(3)  | 3.37(2) d  | 0+  |  |
140mNd  | 2221.4(1) keV  | 600(50) µs  | 7-  |  |
141Nd  | 60  | 81  | 140.909610(4)  | 2.49(3) h  | 3/2+  |  |
141mNd  | 756.51(5) keV  | 62.0(8) s  | 11/2-  |  |
142Nd  | 60  | 82  | 141.9077233(25)  | STABLE  | 0+  | 0.272(5)  | 0.2680-0.2730
143Nd  | 60  | 83  | 142.9098143(25)  | STABLE  | 7/2-  | 0.122(2)  | 0.1212-0.1232
144Nd  | 60  | 84  | 143.9100873(25)  | 2.29(16)E+15 a  | 0+  | 0.238(3)  | 0.2379-0.2397
145Nd  | 60  | 85  | 144.9125736(25)  | STABLE  | 7/2-  | 0.083(1)  | 0.0823-0.0835
146Nd  | 60  | 86  | 145.9131169(25)  | STABLE  | 0+  | 0.172(3)  | 0.1706-0.1735
147Nd  | 60  | 87  | 146.9161004(25)  | 10.98(1) d  | 5/2-  |  |
148Nd  | 60  | 88  | 147.916893(3)  | STABLE [>3.0E+18 a]  | 0+  | 0.057(1)  | 0.0566-0.0578
149Nd  | 60  | 89  | 148.920149(3)  | 1.728(1) h  | 5/2-  |  |
150Nd  | 60  | 90  | 149.920891(3)  | 6.7(7)E+18 a  | 0+  | 0.056(2)  | 0.0553-0.0569
151Nd  | 60  | 91  | 150.923829(3)  | 12.44(7) min  | 3/2+  |  |
152Nd  | 60  | 92  | 151.924682(26)  | 11.4(2) min  | 0+  |  |
153Nd  | 60  | 93  | 152.927698(29)  | 31.6(10) s  | (3/2)-  |  |
154Nd  | 60  | 94  | 153.92948(12)  | 25.9(2) s  | 0+  |  |
154m1Nd  | 480(150)# keV  | 1.3(5) µs  |  |  |
154m2Nd  | 1349(10) keV  | >1 µs  | (5-)  |  |
155Nd  | 60  | 95  | 154.93293(16)#  | 8.9(2) s  | 3/2-#  |  |
156Nd  | 60  | 96  | 155.93502(22)  | 5.49(7) s  | 0+  |  |
156mNd  | 1432(5) keV  | 135 ns  | 5-  |  |
157Nd  | 60  | 97  | 156.93903(21)#  | 2# s [>300 ns]  | 5/2-#  |  |
158Nd  | 60  | 98  | 157.94160(43)#  | 700# ms [>300 ns]  | 0+  |  |
159Nd  | 60  | 99  | 158.94609(54)#  | 500# ms  | 7/2+#  |  |
160Nd  | 60  | 100  | 159.94909(64)#  | 300# ms  | 0+  |  |
161Nd  | 60  | 101  | 160.95388(75)#  | 200# ms  | 1/2-#  |  |

### Notes

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* Evaluated isotopic composition is for most but not all commercial samples.
* Geologically exceptional samples are known in which the isotopic composition lies outside the reported range. The uncertainty in the atomic mass may exceed the stated value for such specimens.
* Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
* Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC which use expanded uncertainties.

## References

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* 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).
* Isotopic compositions and standard atomic masses from Atomic weights of the elements. Review 2000 (IUPAC Technical Report). Pure Appl. Chem. Vol. 75, No. 6, pp. 683-800, (2003) and Atomic Weights Revised (2005).
* 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, Nuc. Phys. A 729, pp. 3-128 (2003).
* National Nuclear Data Center, Brookhaven National Laboratory. Information extracted from the NuDat 2.1 database (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.

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