Isotopes of neodymium

Isotopes of neodymium (60Nd)
Main isotopes[1] Decay
abun­dance half-life (t1/2) mode pro­duct
142Nd 27.2% stable
143Nd 12.2% stable
144Nd 23.8% 2.29×1015 y α 140Ce
145Nd 8.3% stable
146Nd 17.2% stable
148Nd 5.80% stable
150Nd 5.60% 6.7×1018 y β−β− 150Sm
Standard atomic weight Ar°(Nd)
  • 144.242±0.003
  • 144.24±0.01 (abridged)[2][3]

Naturally occurring neodymium (60Nd) is composed of 5 stable isotopes, 142Nd, 143Nd, 145Nd, 146Nd and 148Nd, with 142Nd being the most abundant (27.2% natural abundance), and 2 long-lived radioisotopes, 144Nd and 150Nd. In all, 33 radioisotopes of neodymium have been characterized up to now, with the most stable being naturally occurring isotopes 144Nd (alpha decay, a half-life (t1/2) of 2.29×1015 years) and 150Nd (double beta decay, t1/2 of 7×1018 years). All of the remaining radioactive isotopes have half-lives that are less than 12 days, and the majority of these have half-lives that are less than 70 seconds; the most stable artificial isotope is 147Nd with a half-life of 10.98 days. This element also has 13 known meta states with the most stable being 139mNd (t1/2 5.5 hours), 135mNd (t1/2 5.5 minutes) and 133m1Nd (t1/2 ~70 seconds).

The primary decay modes before the most abundant stable isotope (also the only theoretically stable isotope), 142Nd, are electron capture and positron decay, and the primary mode after is beta decay. The primary decay products before 142Nd are praseodymium isotopes and the primary products after are promethium isotopes.

Neodymium isotopes as fission products

Neodymium is one of the more common fission products that results from the splitting of uranium-233, uranium-235, plutonium-239 and plutonium-241. The distribution of resulting neodymium isotopes is distinctly different than those found in crustal rock formation on Earth. One of the methods used to verify that the Oklo Fossil Reactors in Gabon had produced a natural nuclear fission reactor some two billion years before present was to compare the relative abundances of neodymium isotopes found at the reactor site with those found elsewhere on Earth.[4][5][6]

List of isotopes

Nuclide
[n 1] 		Z N Isotopic mass (Da)
[n 2][n 3] 		Half-life
[n 4][n 5] 		Decay
mode
[n 6] 		Daughter
isotope
[n 7] 		Spin and
parity
[n 8][n 5] 		Natural abundance (mole fraction)
Excitation energy[n 5] Normal proportion Range of variation
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] β+ 126Pr 0+
127Nd 60 67 126.94050(43)# 1.8(4) s β+ 127Pr 5/2+#
β+, p (rare) 126Ce
128Nd 60 68 127.93539(21)# 5# s β+ 128Pr 0+
β+, p (rare) 127Ce
129Nd 60 69 128.93319(22)# 4.9(2) s β+ 129Pr 5/2+#
β+, p (rare) 128Ce
130Nd 60 70 129.92851(3) 21(3) s β+ 130Pr 0+
131Nd 60 71 130.92725(3) 33(3) s β+ 131Pr (5/2)(+#)
β+, p (rare) 130Ce
132Nd 60 72 131.923321(26) 1.56(10) min β+ 132Pr 0+
133Nd 60 73 132.92235(5) 70(10) s β+ 133Pr (7/2+)
133m1Nd 127.97(11) keV ~70 s β+ 133Pr (1/2)+
133m2Nd 176.10(10) keV ~300 ns (9/2–)
134Nd 60 74 133.918790(13) 8.5(15) min β+ 134Pr 0+
134mNd 2293.1(4) keV 410(30) µs (8)–
135Nd 60 75 134.918181(21) 12.4(6) min β+ 135Pr 9/2(–)
135mNd 65.0(2) keV 5.5(5) min β+ 135Pr (1/2+)
136Nd 60 76 135.914976(13) 50.65(33) min β+ 136Pr 0+
137Nd 60 77 136.914567(12) 38.5(15) min β+ 137Pr 1/2+
137mNd 519.43(17) keV 1.60(15) s IT 137Nd (11/2–)
138Nd 60 78 137.911950(13) 5.04(9) h β+ 138Pr 0+
138mNd 3174.9(4) keV 410(50) ns (10+)
139Nd 60 79 138.911978(28) 29.7(5) min β+ 139Pr 3/2+
139m1Nd 231.15(5) keV 5.50(20) h β+ (88.2%) 139Pr 11/2–
IT (11.8%) 139Nd
139m2Nd 2570.9+X keV ≥141 ns
140Nd 60 80 139.90955(3) 3.37(2) d EC 140Pr 0+
140mNd 2221.4(1) keV 600(50) µs 7–
141Nd 60 81 140.909610(4) 2.49(3) h β+ 141Pr 3/2+
141mNd 756.51(5) keV 62.0(8) s IT (99.95%) 141Nd 11/2–
β+ (.05%) 141Pr
142Nd 60 82 141.9077233(25) Stable 0+ 0.272(5) 0.2680–0.2730
143Nd[n 9] 60 83 142.9098143(25) Observationally Stable[n 10] 7/2− 0.122(2) 0.1212–0.1232
144Nd[n 9][n 11] 60 84 143.9100873(25) 2.29(16)×1015 y α 140Ce 0+ 0.238(3) 0.2379–0.2397
145Nd[n 9] 60 85 144.9125736(25) Observationally Stable[n 12] 7/2− 0.083(1) 0.0823–0.0835
146Nd[n 9] 60 86 145.9131169(25) Observationally Stable[n 13] 0+ 0.172(3) 0.1706–0.1735
147Nd[n 9] 60 87 146.9161004(25) 10.98(1) d β− 147Pm 5/2−
148Nd[n 9] 60 88 147.916893(3) Observationally Stable[n 14] 0+ 0.057(1) 0.0566–0.0578
149Nd[n 9] 60 89 148.920149(3) 1.728(1) h β− 149Pm 5/2−
150Nd[n 9][n 11][n 15] 60 90 149.920891(3) 6.7(7)×1018 y β−β− 150Sm 0+ 0.056(2) 0.0553–0.0569
151Nd 60 91 150.923829(3) 12.44(7) min β− 151Pm 3/2+
152Nd 60 92 151.924682(26) 11.4(2) min β− 152Pm 0+
153Nd 60 93 152.927698(29) 31.6(10) s β− 153Pm (3/2)−
154Nd 60 94 153.92948(12) 25.9(2) s β− 154Pm 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 β− 155Pm 3/2−#
156Nd 60 96 155.93502(22) 5.49(7) s β− 156Pm 0+
156mNd 1432(5) keV 135 ns 5−
157Nd 60 97 156.93903(21)# 1.17(4) s[8] β− 157Pm 5/2−#
158Nd 60 98 157.94160(43)# 700# ms [>300 ns] β− 158Pm 0+
159Nd 60 99 158.94609(54)# 500# ms β− 159Pm 7/2+#
160Nd 60 100 159.94909(64)# 300# ms β− 160Pm 0+
161Nd 60 101 160.95388(75)# 200# ms β− 161Pm 1/2−#
This table header & footer:
  1. ^ mNd – Excited nuclear isomer.
  2. ^ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
  3. ^ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
  4. ^ Bold half-life – nearly stable, half-life longer than age of universe.
  5. ^ a b c # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
  6. ^ Modes of decay:
    EC: Electron capture
    IT: Isomeric transition


    p: Proton emission
  7. ^ Bold symbol as daughter – Daughter product is stable.
  8. ^ ( ) spin value – Indicates spin with weak assignment arguments.
  9. ^ a b c d e f g h Fission product
  10. ^ Believed to undergo α decay to 139Ce with a half-life over 3.1×1018 years[1][7]
  11. ^ a b Primordial radionuclide
  12. ^ Believed to undergo α decay to 141Ce with a half-life of over 6×1016 years[1][7]
  13. ^ Believed to undergo β−β− decay to 146Sm or α decay to 142Ce with a half-life of over 1.6×1018 years[1][7]
  14. ^ Believed to undergo β−β− decay to 148Sm or α decay to 144Ce with a half-life of over 3.0×1018 years[1][7]
  15. ^ Predicted to be capable of undergoing triple beta decay and quadruple beta decay with very long partial half-lives

References

  1. ^ a b c d e Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
  2. ^ "Standard Atomic Weights: Neodymium". CIAAW. 2005.
  3. ^ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; et al. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
  4. ^ Hemond, C.; Menet, C.; Menager, M.T. (1991). "U and Nd Isotopes from the New Oklo Reactor 10 (GABON): Evidence for Radioelements Migration". MRS Proceedings. 257. doi:10.1557/PROC-257-489.
  5. ^ "Oklo's Natural Nuclear Reactors". 24 October 2020.
  6. ^ "The Implications of the Oklo Phenomenon on the Constancy of Radiometric Decay Rates".
  7. ^ a b c d Belli, P.; Bernabei, R.; Danevich, F. A.; Incicchitti, A.; Tretyak, V. I. (2019). "Experimental searches for rare alpha and beta decays". European Physical Journal A. 55 (140): 4–6. arXiv:1908.11458. Bibcode:2019EPJA...55..140B. doi:10.1140/epja/i2019-12823-2. S2CID 201664098.
  8. ^ Hartley, D. J.; Kondev, F. G.; Carpenter, M. P.; Clark, J. A.; Copp, P.; Kay, B.; Lauritsen, T.; Savard, G.; Seweryniak, D.; Wilson, G. L.; Wu, J. (2023-08-14). "First β−-decay spectroscopy study of 157Nd". Physical Review C. American Physical Society (APS). 108 (2): 024307. Bibcode:2023PhRvC.108b4307H. doi:10.1103/physrevc.108.024307. ISSN 2469-9985. S2CID 260913513.