Isotopes of neodymium

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. The radioactivity of ¹⁴⁴Nd is due to it having 84 neutrons (two more than 82, which is a magic number corresponding to a stable neutron configuration), and so it may emit an alpha particle (which has 2 neutrons) to form cerium-140 with 82 neutrons.

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. The most stable artificial isotope is ¹⁴⁷Nd, the parent of promethium, 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 lightest and most abundant stable isotope, which is 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.

List of isotopes

|-id=Neodymium-123 | ¹²³Nd | style="text-align:right" | 60 | style="text-align:right" | 63 | | >310&nbsp;ns | | | | | |-id=Neodymium-124 | ¹²⁴Nd | style="text-align:right" | 60 | style="text-align:right" | 64 | 123.95187(54)# | 500#&nbsp;ms<br>[>310&nbsp;ns] | | | 0+ | | |-id=Neodymium-125 | rowspan=2|¹²⁵Nd | rowspan=2 style="text-align:right" | 60 | rowspan=2 style="text-align:right" | 65 | rowspan=2|124.94840(43)# | rowspan=2|0.65(15)&nbsp;s | β⁺ | ¹²⁵Pr | rowspan=2|(5/2)(+#) | rowspan=2| | rowspan=2| |- | β⁺, p (?%) | ¹²⁴Ce |-id=Neodymium-126 | ¹²⁶Nd | style="text-align:right" | 60 | style="text-align:right" | 66 | 125.94269(32)# | 1#&nbsp;s<br />[>310&nbsp;ns] | | | 0+ | | |-id=Neodymium-127 | rowspan=2|¹²⁷Nd | rowspan=2 style="text-align:right" | 60 | rowspan=2 style="text-align:right" | 67 | rowspan=2|126.93998(32)# | rowspan=2|1.8(4)&nbsp;s | β⁺ | ¹²⁷Pr | rowspan=2|5/2+# | rowspan=2| | rowspan=2| |- | β⁺, p (?%) | ¹²⁶Ce |-id=Neodymium-128 | ¹²⁸Nd | style="text-align:right" | 60 | style="text-align:right" | 68 | 127.93502(22)# | 5#&nbsp;s | | | 0+ | | |-id=Neodymium-129 | rowspan=2|¹²⁹Nd | rowspan=2 style="text-align:right" | 60 | rowspan=2 style="text-align:right" | 69 | rowspan=2|128.93304(22)# | rowspan=2|6.8(6)&nbsp;s | β⁺ | ¹²⁹Pr | rowspan=2|7/2− | rowspan=2| | rowspan=2| |- | β⁺, p (?%) | ¹²⁸Ce |-id=Neodymium-129m1 | rowspan=2 style="text-indent:1em" | ^129m1Nd | rowspan=2 colspan="3" style="text-indent:2em" | 17&nbsp;keV | rowspan=2|2.6(4)&nbsp;s | β⁺ | ¹²⁹Pr | rowspan=2|1/2+ | rowspan=2| | rowspan=2| |- | β⁺, p (?%) | ¹²⁸Ce |-id=Neodymium-129m2 | rowspan=2 style="text-indent:1em" | ^129m2Nd | rowspan=2 colspan="3" style="text-indent:2em" | 39&nbsp;keV | rowspan=2|2.6(4)&nbsp;s | β⁺ | ¹²⁹Pr | rowspan=2|3/2+ | rowspan=2| | rowspan=2| |- | β⁺, p (?%) | ¹²⁸Ce |-id=Neodymium-129m3 | rowspan=2 style="text-indent:1em" | ^129m3Nd | rowspan=2 colspan="3" style="text-indent:2em" | 108&nbsp;keV | rowspan=2| | IT (?%) | ^129m2Nd | rowspan=2|5/2+ | rowspan=2| | rowspan=2| |- | IT (?%) | ¹²⁹Nd |-id=Neodymium-129m4 | style="text-indent:1em" | ^129m4Nd | colspan="3" style="text-indent:2em" | 1893&nbsp;keV | | IT | ¹²⁹Nd | (17/2+) | | |-id=Neodymium-129m5 | style="text-indent:1em" | ^129m5Nd | colspan="3" style="text-indent:2em" | 2109&nbsp;keV | | IT | ¹²⁹Nd | (19/2+) | | |-id=Neodymium-129m6 | style="text-indent:1em" | ^129m6Nd | colspan="3" style="text-indent:2em" | 2284&nbsp;keV | 0.48(4)&nbsp;μs | IT | ¹²⁹Nd | (21/2+) | | |-id=Neodymium-130 | ¹³⁰Nd | style="text-align:right" | 60 | style="text-align:right" | 70 | 129.928506(30) | 21(3)&nbsp;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|130.927248(30) | rowspan=2|25.4(9)&nbsp;s | β⁺ | ¹³¹Pr | rowspan=2|(5/2+) | rowspan=2| | rowspan=2| |- | β⁺, p (?%) | ¹³⁰Ce |-id=Neodymium-132 | ¹³²Nd | style="text-align:right" | 60 | style="text-align:right" | 72 | 131.923321(26) | 1.56(10)&nbsp;min | β⁺ | ¹³²Pr | 0+ | | |-id=Neodymium-133 | ¹³³Nd | style="text-align:right" | 60 | style="text-align:right" | 73 | 132.922348(50) | 70(10)&nbsp;s | β⁺ | ¹³³Pr | (7/2+) | | |-id=Neodymium-133m1 | rowspan=2 style="text-indent:1em" | ^133m1Nd | rowspan=2 colspan="3" style="text-indent:2em" | 127.97(12)&nbsp;keV | rowspan=2|~70&nbsp;s | β⁺ (?%) | ¹³³Pr | rowspan=2|(1/2)+ | rowspan=2| | rowspan=2| |- | IT (?%) | ¹³³Nd |-id=Neodymium-133m2 | style="text-indent:1em" | ^133m2Nd | colspan="3" style="text-indent:2em" | 176.10(10)&nbsp;keV | 301(18)&nbsp;ns | IT | ¹³³Nd | (9/2–) | | |-id=Neodymium-134 | ¹³⁴Nd | style="text-align:right" | 60 | style="text-align:right" | 74 | 133.918790(13) | 8.5(15)&nbsp;min | β⁺ | ¹³⁴Pr | 0+ | | |-id=Neodymium-134m | style="text-indent:1em" | ^134mNd | colspan="3" style="text-indent:2em" | 2293.0(4)&nbsp;keV | 389(17)&nbsp;μs | IT | ¹³⁴Nd | 8– | | |-id=Neodymium-135 | ¹³⁵Nd | style="text-align:right" | 60 | style="text-align:right" | 75 | 134.918181(21) | 12.4(6)&nbsp;min | β⁺ | ¹³⁵Pr | 9/2– | | |-id=Neodymium-135m | style="text-indent:1em" | ^135mNd | colspan="3" style="text-indent:2em" | 64.95(24)&nbsp;keV | 5.5(5)&nbsp;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)&nbsp;min | β⁺ | ¹³⁶Pr | 0+ | | |-id=Neodymium-137 | ¹³⁷Nd | style="text-align:right" | 60 | style="text-align:right" | 77 | 136.914563(13) | 38.5(15)&nbsp;min | β⁺ | ¹³⁷Pr | 1/2+ | | |-id=Neodymium-137m | style="text-indent:1em" | ^137mNd | colspan="3" style="text-indent:2em" | 519.43(20)&nbsp;keV | 1.60(15)&nbsp;s | IT | ¹³⁷Nd | 11/2– | | |-id=Neodymium-138 | ¹³⁸Nd | style="text-align:right" | 60 | style="text-align:right" | 78 | 137.911951(12) | 5.04(9)&nbsp;h | β⁺ | ¹³⁸Pr | 0+ | | |-id=Neodymium-138m | style="text-indent:1em" | ^138mNd | colspan="3" style="text-indent:2em" | 3174.5(4)&nbsp;keV | 370(5)&nbsp;ns | IT | ¹³⁸Nd | 10+ | | |-id=Neodymium-139 | ¹³⁹Nd | style="text-align:right" | 60 | style="text-align:right" | 79 | 138.911951(30) | 29.7(5)&nbsp;min | β⁺ | ¹³⁹Pr | 3/2+ | | |-id=Neodymium-139m1 | rowspan=2 style="text-indent:1em" | ^139m1Nd | rowspan=2 colspan="3" style="text-indent:2em" | 231.16(5)&nbsp;keV | rowspan=2|5.50(20)&nbsp;h | β⁺ (87.0%) | ¹³⁹Pr | rowspan=2|11/2– | rowspan=2| | rowspan=2| |- | IT (13.0%) | ¹³⁹Nd |-id=Neodymium-139m2 | style="text-indent:1em" | ^139m2Nd | colspan="3" style="text-indent:2em" | 2616.9(6)&nbsp;keV | 276.8(18)&nbsp;ns | IT | ¹³⁹Nd | 23/2 | | |-id=Neodymium-140 | ¹⁴⁰Nd | style="text-align:right" | 60 | style="text-align:right" | 80 | 139.9095461(35) | 3.37(2)&nbsp;d | EC | ¹⁴⁰Pr | 0+ | | |-id=Neodymium-140m1 | style="text-indent:1em" | ^140m1Nd | colspan="3" style="text-indent:2em" | 2221.65(9)&nbsp;keV | 600(50)&nbsp;μs | IT | ¹⁴⁰Nd | 7– | | |-id=Neodymium-140m2 | style="text-indent:1em" | ^140m2Nd | colspan="3" style="text-indent:2em" | 7435.1(4)&nbsp;keV | 1.22(6)&nbsp;μs | IT | ¹⁴⁰Nd | 20+ | | |-id=Neodymium-141 | rowspan=2|¹⁴¹Nd | rowspan=2 style="text-align:right" | 60 | rowspan=2 style="text-align:right" | 81 | rowspan=2|140.9096167(34) | rowspan=2|2.49(3)&nbsp;h | EC (97.28%) | rowspan=2|¹⁴¹Pr | rowspan=2|3/2+ | rowspan=2| | rowspan=2| |- | β⁺ (2.72%) |-id=Neodymium-141m | rowspan=2 style="text-indent:1em" | ^141mNd | rowspan=2 colspan="3" style="text-indent:2em" | 756.51(5)&nbsp;keV | rowspan=2|62.0(8)&nbsp;s | IT (99.97%) | ¹⁴¹Nd | rowspan=2|11/2– | rowspan=2| | rowspan=2| |- | β⁺ (0.032%) | ¹⁴¹Pr |-id=Neodymium-142 | ¹⁴²Nd | style="text-align:right" | 60 | style="text-align:right" | 82 | 141.9077288(13) | colspan=3 align=center|Stable | 0+ | 0.27153(40) | |-id=Neodymium-143 | ¹⁴³Nd | style="text-align:right" | 60 | style="text-align:right" | 83 | 142.9098198(13) | colspan=3 align=center|Observationally Stable | 7/2− | 0.12173(26) | |-id=Neodymium-144 | ¹⁴⁴Nd | style="text-align:right" | 60 | style="text-align:right" | 84 | 143.9100928(13) | 2.29(16)×10¹⁵&nbsp;y | α | ¹⁴⁰Ce | 0+ | 0.23798(19) | |-id=Neodymium-145 | ¹⁴⁵Nd | style="text-align:right" | 60 | style="text-align:right" | 85 | 144.9125792(14) | colspan=3 align=center|Observationally Stable | 7/2− | 0.08293(12) | |-id=Neodymium-146 | ¹⁴⁶Nd | style="text-align:right" | 60 | style="text-align:right" | 86 | 145.9131225(14) | colspan=3 align=center|Observationally Stable | 0+ | 0.17189(32) | |-id=Neodymium-147 | ¹⁴⁷Nd | style="text-align:right" | 60 | style="text-align:right" | 87 | 146.9161060(14) | 10.98(1)&nbsp;d | β^− | ¹⁴⁷Pm | 5/2− | | |-id=Neodymium-148 | ¹⁴⁸Nd | style="text-align:right" | 60 | style="text-align:right" | 88 | 147.9168990(22) | colspan=3 align=center|Observationally Stable | 0+ | 0.05756(21) | |-id=Neodymium-149 | ¹⁴⁹Nd | style="text-align:right" | 60 | style="text-align:right" | 89 | 148.9201546(22) | 1.728(1)&nbsp;h | β^− | ¹⁴⁹Pm | 5/2− | | |-id=Neodymium-150 | ¹⁵⁰Nd | style="text-align:right" | 60 | style="text-align:right" | 90 | 149.9209013(12) | 9.3(7)×10¹⁸&nbsp;y | β^−β^− | ¹⁵⁰Sm | 0+ | 0.05638(28) | |-id=Neodymium-151 | ¹⁵¹Nd | style="text-align:right" | 60 | style="text-align:right" | 91 | 150.9238394(12) | 12.44(7)&nbsp;min | β^− | ¹⁵¹Pm | 3/2+ | | |-id=Neodymium-152 | ¹⁵²Nd | style="text-align:right" | 60 | style="text-align:right" | 92 | 151.924691(26) | 11.4(2)&nbsp;min | β^− | ¹⁵²Pm | 0+ | | |-id=Neodymium-153 | ¹⁵³Nd | style="text-align:right" | 60 | style="text-align:right" | 93 | 152.9277179(29) | 31.6(10)&nbsp;s | β^− | ¹⁵³Pm | (3/2)− | | |-id=Neodymium-153m | style="text-indent:1em" | ^153mNd | colspan="3" style="text-indent:2em" | 191.71(16)&nbsp;keV | 1.10(4)&nbsp;μs | IT | ¹⁵³Nd | (5/2)+ | | |-id=Neodymium-154 | ¹⁵⁴Nd | style="text-align:right" | 60 | style="text-align:right" | 94 | 153.9295974(11) | 25.9(2)&nbsp;s | β^− | ¹⁵⁴Pm | 0+ | | |-id=Neodymium-154m | style="text-indent:1em" | ^154mNd | colspan="3" style="text-indent:2em" | 1297.9(4)&nbsp;keV | 3.2(3)&nbsp;μs | IT | ¹⁵⁴Nd | (4−) | | |-id=Neodymium-155 | ¹⁵⁵Nd | style="text-align:right" | 60 | style="text-align:right" | 95 | 154.9331356(98) | 8.9(2)&nbsp;s | β^− | ¹⁵⁵Pm | (3/2−) | | |-id=Neodymium-156 | ¹⁵⁶Nd | style="text-align:right" | 60 | style="text-align:right" | 96 | 155.9353704(14) | 5.06(13)&nbsp;s | β^− | ¹⁵⁶Pm | 0+ | | |-id=Neodymium-156m | style="text-indent:1em" | ^156mNd | colspan="3" style="text-indent:2em" | 1431.3(4)&nbsp;keV | 365(145)&nbsp;ns | IT | ¹⁵⁶Nd | 5− | | |-id=Neodymium-157 | ¹⁵⁷Nd | style="text-align:right" | 60 | style="text-align:right" | 97 | 156.9393511(23) | 1.17(4)&nbsp;s | β^− | ¹⁵⁷Pm | 5/2−# | | |-id=Neodymium-158 | ¹⁵⁸Nd | style="text-align:right" | 60 | style="text-align:right" | 98 | 157.9422056(14) | 810(30)&nbsp;ms | β^− | ¹⁵⁸Pm | 0+ | | |-id=Neodymium-158m | style="text-indent:1em" | ^158mNd | colspan="3" style="text-indent:2em" | 1648.1(14)&nbsp;keV | 339(20)&nbsp;ns | IT | ¹⁵⁸Nd | (6−) | | |-id=Neodymium-159 | ¹⁵⁹Nd | style="text-align:right" | 60 | style="text-align:right" | 99 | 158.946619(32) | 500(30)&nbsp;ms | β^− | ¹⁵⁹Pm | 7/2+# | | |-id=Neodymium-160 | ¹⁶⁰Nd | style="text-align:right" | 60 | style="text-align:right" | 100 | 159.949839(50) | 439(37)&nbsp;ms | β^− | ¹⁶⁰Pm | 0+ | | |-id=Neodymium-160m | style="text-indent:1em" | ^160mNd | colspan="3" style="text-indent:2em" | 1107.9(9)&nbsp;keV | 1.63(21)&nbsp;μs | IT | ¹⁶⁰Nd | (4−) | | |-id=Neodymium-161 | ¹⁶¹Nd | style="text-align:right" | 60 | style="text-align:right" | 101 | 160.95466(43)# | 215(76)&nbsp;ms | β^− | ¹⁶¹Pm | 1/2−# | | |-id=Neodymium-162 | ¹⁶²Nd | style="text-align:right" | 60 | style="text-align:right" | 102 | 161.95812(43)# | 310(200)&nbsp;ms | β^− | ¹⁶²Pm | 0+ | | |-id=Neodymium-163 | ¹⁶³Nd | style="text-align:right" | 60 | style="text-align:right" | 103 | 162.96341(54)# | 80#&nbsp;ms<br />[>550&nbsp;ns] | | | 5/2−# | |

See also

Daughter products other than neodymium

• Isotopes of samarium
• Isotopes of promethium
• Isotopes of praseodymium
• Isotopes of cerium

References

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