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, 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_½) of 2.29×10¹⁵ years) and ¹⁵⁰Nd (double beta decay, T_½ 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 (T_½ 5.5 hours), ^135mNd (T_½ 5.5 minutes) and ^133m1Nd (T_½ ~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

nuclide symbol	Z(p)	N(n)	isotopic mass (u)	half-life^{[n 1]}	decay mode(s)^[1]^{[n 2]}	daughter isotope(s)^{[n 3]}	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
nuclide symbol	excitation energy			half-life^{[n 1]}	decay mode(s)^[1]^{[n 2]}	daughter isotope(s)^{[n 3]}	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
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)	Observationally Stable^{[n 4]}			0+	0.272(5)	0.2680-0.2730
¹⁴³Nd^{[n 5]}^{[n 6]}	60	83	142.9098143(25)	Observationally Stable^{[n 7]}			7/2-	0.122(2)	0.1212-0.1232
¹⁴⁴Nd^{[n 8]}^{[n 5]}	60	84	143.9100873(25)	2.29(16)×10¹⁵ a	α	¹⁴⁰Ce	0+	0.238(3)	0.2379-0.2397
¹⁴⁵Nd^{[n 5]}	60	85	144.9125736(25)	Observationally Stable^{[n 9]}			7/2-	0.083(1)	0.0823-0.0835
¹⁴⁶Nd^{[n 5]}	60	86	145.9131169(25)	Observationally Stable^{[n 10]}			0+	0.172(3)	0.1706-0.1735
¹⁴⁷Nd^{[n 5]}	60	87	146.9161004(25)	10.98(1) d	β^-	¹⁴⁷Pm	5/2-
¹⁴⁸Nd^{[n 5]}	60	88	147.916893(3)	Observationally Stable^{[n 11]}			0+	0.057(1)	0.0566-0.0578
¹⁴⁹Nd^{[n 5]}	60	89	148.920149(3)	1.728(1) h	β^-	¹⁴⁸Pm	5/2-
¹⁵⁰Nd^{[n 8]}^{[n 5]}	60	90	149.920891(3)	6.7(7)×10¹⁸ a	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)#	2# s [>300 ns]	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-#

^ Bold for isotopes with half-lives longer than the age of the universe (nearly stable)
^ Abbreviations:
EC: Electron capture
IT: Isomeric transition
^ Bold for stable isotopes
^ Theoretically capable of Spontaneous fission
^ ^a ^b ^c ^d ^e ^f ^g ^h Fission product
^ Used in Samarium-neodymium dating
^ Theorized to undergo α decay to ¹³⁹Ce
^ ^a ^b Primordial radionuclide
^ Theorized to undergo α decay to ¹⁴¹Ce
^ Theorized to undergo α decay to ¹⁴²Ce
^ Theorized to undergo α decay to ¹⁴⁴Ce with a half-life over 3.0×10¹⁸ years

Notes

Evaluation of isotopic composition is for most but not all commercial samples.
Geologicallyy 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

^ http://www.nucleonica.net/unc.aspx

Isotope masses from:
- G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (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. http://www.nndc.bnl.gov/amdc/nubase/Nubase2003.pdf.
Isotopic compositions and standard atomic masses from:
- J. R. de Laeter, J. K. Böhlke, P. De Bièvre, H. Hidaka, H. S. Peiser, K. J. R. Rosman and P. D. P. Taylor (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry 75 (6): 683–800. doi:10.1351/pac200375060683. http://www.iupac.org/publications/pac/75/6/0683/pdf/.
- M. E. Wieser (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry 78 (11): 2051–2066. doi:10.1351/pac200678112051. http://iupac.org/publications/pac/78/11/2051/pdf/. Lay summary.
Half-life, spin, and isomer data selected from the following sources. See editing notes on this article's talk page.
- G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (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. http://www.nndc.bnl.gov/amdc/nubase/Nubase2003.pdf.
- National Nuclear Data Center. "NuDat 2.1 database". Brookhaven National Laboratory. http://www.nndc.bnl.gov/nudat2/. Retrieved September 2005.
- N. E. Holden (2004). "Table of the Isotopes". In D. R. Lide. CRC Handbook of Chemistry and Physics (85th ed.). CRC Press. Section 11. ISBN 978-0849304859.

Isotopes of praseodymium	Isotopes of neodymium	Isotopes of promethium
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