Isotopes of neodymium explained

Naturally occurring neodymium (₆₀Nd) is composed of five stable isotopes, ¹⁴²Nd, ¹⁴³Nd, ¹⁴⁵Nd, ¹⁴⁶Nd and ¹⁴⁸Nd, with ¹⁴²Nd being the most abundant (27.2% natural abundance), and two long-lived radioisotopes, ¹⁴⁴Nd and ¹⁵⁰Nd. In all, 35 radioisotopes of neodymium have been characterized up to now, with the most stable being naturally occurring isotopes ¹⁴⁴Nd (alpha decay, a half-life (t_1/2) of years) and ¹⁵⁰Nd (double beta decay, t_1/2 of years), and for practical purposes they can be considered to be stable as well. 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 15 known meta states with the most stable being ^139mNd (t_1/2 5.5 hours), ^135mNd (t_1/2 5.5 minutes) and ^133m1Nd (t_1/2 ~70 seconds).

The primary decay modes for isotopes lighter than the most abundant stable isotope (also the only theoretically stable isotope), ¹⁴²Nd, are electron capture and positron decay, and the primary mode for heavier radioisotopes is beta decay. The primary decay products for lighter radioisotopes are praseodymium isotopes and the primary products for heavier ones 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.^{[1] [2] [3]}

List of isotopes

|-id=Neodymium-124| ¹²⁴Nd| style="text-align:right" | 60| style="text-align:right" | 64| 123.95223(64)#| 500# ms||| 0+|||-id=Neodymium-125| ¹²⁵Nd| style="text-align:right" | 60| style="text-align:right" | 65| 124.94888(43)#| 600(150) ms||| 5/2(+#)|||-id=Neodymium-126| ¹²⁶Nd| style="text-align:right" | 60| style="text-align:right" | 66| 125.94322(43)#| 1# s [>200 ns]| β⁺| ¹²⁶Pr| 0+|||-id=Neodymium-127| rowspan=2|¹²⁷Nd| rowspan=2 style="text-align:right" | 60| rowspan=2 style="text-align:right" | 67| rowspan=2|126.94050(43)#| rowspan=2|1.8(4) s| β⁺| ¹²⁷Pr| rowspan=2|5/2+#| rowspan=2|| rowspan=2||-| β⁺, p (rare)| ¹²⁶Ce|-id=Neodymium-128| rowspan=2|¹²⁸Nd| rowspan=2 style="text-align:right" | 60| rowspan=2 style="text-align:right" | 68| rowspan=2|127.93539(21)#| rowspan=2|5# s| β⁺| ¹²⁸Pr| rowspan=2|0+| rowspan=2|| rowspan=2||-| β⁺, p (rare)| ¹²⁷Ce|-id=Neodymium-129| rowspan=2|¹²⁹Nd| rowspan=2 style="text-align:right" | 60| rowspan=2 style="text-align:right" | 69| rowspan=2|128.93319(22)#| rowspan=2|4.9(2) s| β⁺| ¹²⁹Pr| rowspan=2|5/2+#| rowspan=2| | rowspan=2||-| β⁺, p (rare)| ¹²⁸Ce|-id=Neodymium-130| ¹³⁰Nd| style="text-align:right" | 60| style="text-align:right" | 70| 129.92851(3)| 21(3) s| β⁺| ¹³⁰Pr| 0+|||-id=Neodymium-131| rowspan=2|¹³¹Nd| rowspan=2 style="text-align:right" | 60| rowspan=2 style="text-align:right" | 71| rowspan=2|130.92725(3)| rowspan=2|33(3) s| β⁺| ¹³¹Pr| rowspan=2|(5/2)(+#)| rowspan=2| | rowspan=2||-| β⁺, p (rare)| ¹³⁰Ce|-id=Neodymium-132| ¹³²Nd| style="text-align:right" | 60| style="text-align:right" | 72| 131.923321(26)| 1.56(10) min| β⁺| ¹³²Pr| 0+|||-id=Neodymium-133| ¹³³Nd| style="text-align:right" | 60| style="text-align:right" | 73| 132.92235(5)| 70(10) s| β⁺| ¹³³Pr| (7/2+)|||-id=Neodymium-133m1| style="text-indent:1em" | ^133m1Nd| colspan="3" style="text-indent:2em" | 127.97(11) keV| ~70 s| β⁺| ¹³³Pr| (1/2)+|||-id=Neodymium-133m2| style="text-indent:1em" | ^133m2Nd| colspan="3" style="text-indent:2em" | 176.10(10) keV| ~300 ns||| (9/2–)|||-id=Neodymium-134| ¹³⁴Nd| style="text-align:right" | 60| style="text-align:right" | 74| 133.918790(13)| 8.5(15) min| β⁺| ¹³⁴Pr| 0+|||-id=Neodymium-134m| style="text-indent:1em" | ^134mNd| colspan="3" style="text-indent:2em" | 2293.1(4) keV| 410(30) μs||| (8)–|||-id=Neodymium-135| ¹³⁵Nd| style="text-align:right" | 60| style="text-align:right" | 75| 134.918181(21)| 12.4(6) min| β⁺| ¹³⁵Pr| 9/2(–)|||-id=Neodymium-135m| style="text-indent:1em" | ^135mNd| colspan="3" style="text-indent:2em" | 65.0(2) keV| 5.5(5) min| β⁺| ¹³⁵Pr| (1/2+)|||-id=Neodymium-136| ¹³⁶Nd| style="text-align:right" | 60| style="text-align:right" | 76| 135.914976(13)| 50.65(33) min| β⁺| ¹³⁶Pr| 0+|||-id=Neodymium-137| ¹³⁷Nd| style="text-align:right" | 60| style="text-align:right" | 77| 136.914567(12)| 38.5(15) min| β⁺| ¹³⁷Pr| 1/2+|||-id=Neodymium-137m| style="text-indent:1em" | ^137mNd| colspan="3" style="text-indent:2em" | 519.43(17) keV| 1.60(15) s| IT| ¹³⁷Nd| (11/2–)|||-id=Neodymium-138| ¹³⁸Nd| style="text-align:right" | 60| style="text-align:right" | 78| 137.911950(13)| 5.04(9) h| β⁺| ¹³⁸Pr| 0+|||-id=Neodymium-138m| style="text-indent:1em" | ^138mNd| colspan="3" style="text-indent:2em" | 3174.9(4) keV| 410(50) ns||| (10+)|||-id=Neodymium-139| ¹³⁹Nd| style="text-align:right" | 60| style="text-align:right" | 79| 138.911978(28)| 29.7(5) min| β⁺| ¹³⁹Pr| 3/2+|||-id=Neodymium-139m1| rowspan=2 style="text-indent:1em" | ^139m1Nd| rowspan=2 colspan="3" style="text-indent:2em" | 231.15(5) keV| rowspan=2|5.50(20) h| β⁺ (88.2%)| ¹³⁹Pr| rowspan=2|11/2–| rowspan=2|| rowspan=2||-| IT (11.8%)| ¹³⁹Nd|-id=Neodymium-139m2| style="text-indent:1em" | ^139m2Nd| colspan="3" style="text-indent:2em" | 2570.9+X keV| ≥141 ns||||||-id=Neodymium-140| ¹⁴⁰Nd| style="text-align:right" | 60| style="text-align:right" | 80| 139.90955(3)| 3.37(2) d| EC| ¹⁴⁰Pr| 0+|||-id=Neodymium-140m| style="text-indent:1em" | ^140mNd| colspan="3" style="text-indent:2em" | 2221.4(1) keV| 600(50) μs||| 7–|||-id=Neodymium-141| ¹⁴¹Nd| style="text-align:right" | 60| style="text-align:right" | 81| 140.909610(4)| 2.49(3) h| β⁺| ¹⁴¹Pr| 3/2+|||-id=Neodymium-141m| rowspan=2 style="text-indent:1em" | ^141mNd| rowspan=2 colspan="3" style="text-indent:2em" | 756.51(5) keV| rowspan=2|62.0(8) s| IT (99.95%)| ¹⁴¹Nd| rowspan=2|11/2–| rowspan=2|| rowspan=2||-| β⁺ (.05%)| ¹⁴¹Pr|-id=Neodymium-142| ¹⁴²Nd| style="text-align:right" | 60| style="text-align:right" | 82| 141.9077233(25)| colspan=3 align=center|Stable| 0+| 0.272(5)| 0.2680–0.2730|-id=Neodymium-143| ¹⁴³Nd^[4] | style="text-align:right" | 60| style="text-align:right" | 83| 142.9098143(25)| colspan=3 align=center|Observationally Stable| 7/2−| 0.122(2)| 0.1212–0.1232|-id=Neodymium-144| ¹⁴⁴Nd^[5] | style="text-align:right" | 60| style="text-align:right" | 84| 143.9100873(25)| 2.29(16)×10¹⁵ y| α| ¹⁴⁰Ce| 0+| 0.238(3)| 0.2379–0.2397|-id=Neodymium-145| ¹⁴⁵Nd| style="text-align:right" | 60| style="text-align:right" | 85| 144.9125736(25)| colspan=3 align=center|Observationally Stable| 7/2−| 0.083(1)| 0.0823–0.0835|-id=Neodymium-146| ¹⁴⁶Nd| style="text-align:right" | 60| style="text-align:right" | 86| 145.9131169(25)| colspan=3 align=center|Observationally Stable| 0+| 0.172(3)| 0.1706–0.1735|-id=Neodymium-147| ¹⁴⁷Nd| style="text-align:right" | 60| style="text-align:right" | 87| 146.9161004(25)| 10.98(1) d| β⁻| ¹⁴⁷Pm| 5/2−|||-id=Neodymium-148| ¹⁴⁸Nd| style="text-align:right" | 60| style="text-align:right" | 88| 147.916893(3)| colspan=3 align=center|Observationally Stable| 0+| 0.057(1)| 0.0566–0.0578|-id=Neodymium-149| ¹⁴⁹Nd| style="text-align:right" | 60| style="text-align:right" | 89| 148.920149(3)| 1.728(1) h| β⁻| ¹⁴⁹Pm| 5/2−|||-id=Neodymium-150| ¹⁵⁰Nd^[6] | style="text-align:right" | 60| style="text-align:right" | 90| 149.920891(3)| 9.3(7)×10¹⁸ y| β⁻β⁻| ¹⁵⁰Sm| 0+| 0.056(2)| 0.0553–0.0569|-id=Neodymium-151| ¹⁵¹Nd| style="text-align:right" | 60| style="text-align:right" | 91| 150.923829(3)| 12.44(7) min| β⁻| ¹⁵¹Pm| 3/2+|||-id=Neodymium-152| ¹⁵²Nd| style="text-align:right" | 60| style="text-align:right" | 92| 151.924682(26)| 11.4(2) min| β⁻| ¹⁵²Pm| 0+|||-id=Neodymium-153| ¹⁵³Nd| style="text-align:right" | 60| style="text-align:right" | 93| 152.927698(29)| 31.6(10) s| β⁻| ¹⁵³Pm| (3/2)−|||-id=Neodymium-154| ¹⁵⁴Nd| style="text-align:right" | 60| style="text-align:right" | 94| 153.92948(12)| 25.9(2) s| β⁻| ¹⁵⁴Pm| 0+|||-id=Neodymium-154m1| style="text-indent:1em" | ^154m1Nd| colspan="3" style="text-indent:2em" | 480(150)# keV| 1.3(5) μs||||||-id=Neodymium-154m2| style="text-indent:1em" | ^154m2Nd| colspan="3" style="text-indent:2em" | 1349(10) keV| >1 μs||| (5−)|||-id=Neodymium-155| ¹⁵⁵Nd| style="text-align:right" | 60| style="text-align:right" | 95| 154.93293(16)#| 8.9(2) s| β⁻| ¹⁵⁵Pm| 3/2−#|||-id=Neodymium-156| ¹⁵⁶Nd| style="text-align:right" | 60| style="text-align:right" | 96| 155.93502(22)| 5.49(7) s| β⁻| ¹⁵⁶Pm| 0+|||-id=Neodymium-156m| style="text-indent:1em" | ^156mNd| colspan="3" style="text-indent:2em" | 1432(5) keV| 135 ns||| 5−|||-id=Neodymium-157| ¹⁵⁷Nd| style="text-align:right" | 60| style="text-align:right" | 97| 156.93903(21)#| 1.17(4) s^[7] | β⁻| ¹⁵⁷Pm| 5/2−#|||-id=Neodymium-158| ¹⁵⁸Nd| style="text-align:right" | 60| style="text-align:right" | 98| 157.94160(43)#| 810(30) ms| β⁻| ¹⁵⁸Pm| 0+|||-id=Neodymium-158m| style="text-indent:1em" | ^158mNd| colspan="3" style="text-indent:2em" | 1648.1(14) keV| | IT| ¹⁶⁰Nd| (6−)|||-id=Neodymium-159| ¹⁵⁹Nd| style="text-align:right" | 60| style="text-align:right" | 99| 158.94609(54)#| 500(30) ms| β⁻| ¹⁵⁹Pm| 7/2+#|||-id=Neodymium-160| ¹⁶⁰Nd| style="text-align:right" | 60| style="text-align:right" | 100| 159.94909(64)#| 439(37) ms| β⁻| ¹⁶⁰Pm| 0+|||-id=Neodymium-160m| style="text-indent:1em" | ^160mNd| colspan="3" style="text-indent:2em" | 1107.9(9) keV| | IT| ¹⁶⁰Nd| (4−)|||-id=Neodymium-161| ¹⁶¹Nd| style="text-align:right" | 60| style="text-align:right" | 101| 160.95388(75)#| 215(76) ms| β⁻| ¹⁶¹Pm| 1/2−#|||-id=Neodymium-162| ¹⁶²Nd| style="text-align:right" | 60| style="text-align:right" | 102| | 310(200) ms| β⁻| ¹⁶²Pm| 0+|||-id=Neodymium-163| ¹⁶³Nd| style="text-align:right" | 60| style="text-align:right" | 103| | 80# ms| β⁻| ¹⁶³Pm| 5/2−#||

References

• Isotope masses from:
  • • Isotopic compositions and standard atomic masses from:
      • • Half-life, spin, and isomer data selected from the following sources.

Notes and References

1. U and Nd Isotopes from the New Oklo Reactor 10 (GABON): Evidence for Radioelements Migration . 10.1557/PROC-257-489 . 1991 . Hemond . C. . Menet . C. . Menager . M.T. . MRS Proceedings . 257 .
2. Web site: Oklo's Natural Nuclear Reactors . 24 October 2020 .
3. Web site: The Implications of the Oklo Phenomenon on the Constancy of Radiometric Decay Rates .
4. Fission product
5. [Primordial nuclide|Primordial]
6. Predicted to be capable of undergoing triple beta decay and quadruple beta decay with very long partial half-lives
7. 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. . First β⁻-decay spectroscopy study of ¹⁵⁷Nd . Physical Review C . American Physical Society (APS) . 108 . 2 . 2023-08-14 . 024307 . 2469-9985 . 10.1103/physrevc.108.024307. 2023PhRvC.108b4307H . 260913513 .