Isotopes of neodymium

Isotopes of neodymium (₆₀Nd)
Standard atomic weight Ar°(Nd)
	144.242±0.003; 144.24±0.01 (abridged);
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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 (t_1/2) of 2.29×10¹⁵ years) and ¹⁵⁰Nd (double beta decay, t_1/2 of 7×10¹⁸ 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 13 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 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)
Nuclide ^{[n 1]}	Excitation energy^{[n 5]}			Half-life ^{[n 4]}^{[n 5]}	Decay mode ^{[n 6]}	Daughter isotope ^{[n 7]}	Spin and parity ^{[n 8]}^{[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+#
¹²⁷Nd	60	67	126.94050(43)#	1.8(4) s	β⁺, p (rare)	¹²⁶Ce	5/2+#
¹²⁸Nd	60	68	127.93539(21)#	5# s	β⁺	¹²⁸Pr	0+
¹²⁸Nd	60	68	127.93539(21)#	5# s	β⁺, p (rare)	¹²⁷Ce	0+
¹²⁹Nd	60	69	128.93319(22)#	4.9(2) s	β⁺	¹²⁹Pr	5/2+#
¹²⁹Nd	60	69	128.93319(22)#	4.9(2) s	β⁺, p (rare)	¹²⁸Ce	5/2+#
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)(+#)
¹³¹Nd	60	71	130.92725(3)	33(3) s	β⁺, p (rare)	¹³⁰Ce	(5/2)(+#)
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–
^139m1Nd	231.15(5) keV			5.50(20) h	IT (11.8%)	¹³⁹Nd	11/2–
^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–
^141mNd	756.51(5) keV			62.0(8) s	β⁺ (.05%)	¹⁴¹Pr	11/2–
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)	9.3(7)×10¹⁸ y^[1]	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^[9]	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−#
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References

Isotope masses from:
- Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
Isotopic compositions and standard atomic masses from:
- de Laeter, John Robert; Böhlke, John Karl; De Bièvre, Paul; Hidaka, Hiroshi; Peiser, H. Steffen; Rosman, Kevin J. R.; Taylor, Philip D. P. (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.
- Wieser, Michael E. (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry. 78 (11): 2051–2066. doi:10.1351/pac200678112051.
"News & Notices: Standard Atomic Weights Revised". International Union of Pure and Applied Chemistry. 19 October 2005.
Half-life, spin, and isomer data selected from the following sources.
- Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
- National Nuclear Data Center. "NuDat 2.x database". Brookhaven National Laboratory.
- Holden, Norman E. (2004). "11. Table of the Isotopes". In Lide, David R. (ed.). CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, Florida: CRC Press. ISBN 978-0-8493-0485-9.

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