Isotopes of neodymium

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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, 31 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

[edit] Table

nuclide symbol	Z(p)	N(n)	isotopic mass (u)	half-life	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
	excitation energy
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]	0+
127Nd	60	67	126.94050(43)#	1.8(4) s	5/2+#
128Nd	60	68	127.93539(21)#	5# s	0+
129Nd	60	69	128.93319(22)#	4.9(2) s	5/2+#
130Nd	60	70	129.92851(3)	21(3) s	0+
131Nd	60	71	130.92725(3)	33(3) s	(5/2)(+#)
132Nd	60	72	131.923321(26)	1.56(10) min	0+
133Nd	60	73	132.92235(5)	70(10) s	(7/2+)
133m1Nd	127.97(11) keV			~70 s	(1/2)+
133m2Nd	176.10(10) keV			~300 ns	(9/2-)
134Nd	60	74	133.918790(13)	8.5(15) min	0+
134mNd	2293.1(4) keV			410(30) µs	(8)-
135Nd	60	75	134.918181(21)	12.4(6) min	9/2(-)
135mNd	65.0(2) keV			5.5(5) min	(1/2+)
136Nd	60	76	135.914976(13)	50.65(33) min	0+
137Nd	60	77	136.914567(12)	38.5(15) min	1/2+
137mNd	519.43(17) keV			1.60(15) s	(11/2-)
138Nd	60	78	137.911950(13)	5.04(9) h	0+
138mNd	3174.9(4) keV			410(50) ns	(10+)
139Nd	60	79	138.911978(28)	29.7(5) min	3/2+
139m1Nd	231.15(5) keV			5.50(20) h	11/2-
139m2Nd	2570.9+X keV			>=141 ns
140Nd	60	80	139.90955(3)	3.37(2) d	0+
140mNd	2221.4(1) keV			600(50) µs	7-
141Nd	60	81	140.909610(4)	2.49(3) h	3/2+
141mNd	756.51(5) keV			62.0(8) s	11/2-
142Nd	60	82	141.9077233(25)	STABLE	0+	0.272(5)	0.2680-0.2730
143Nd	60	83	142.9098143(25)	STABLE	7/2-	0.122(2)	0.1212-0.1232
144Nd	60	84	143.9100873(25)	2.29(16)E+15 a	0+	0.238(3)	0.2379-0.2397
145Nd	60	85	144.9125736(25)	STABLE	7/2-	0.083(1)	0.0823-0.0835
146Nd	60	86	145.9131169(25)	STABLE	0+	0.172(3)	0.1706-0.1735
147Nd	60	87	146.9161004(25)	10.98(1) d	5/2-
148Nd	60	88	147.916893(3)	STABLE [>3.0E+18 a]	0+	0.057(1)	0.0566-0.0578
149Nd	60	89	148.920149(3)	1.728(1) h	5/2-
150Nd	60	90	149.920891(3)	6.7(7)E+18 a	0+	0.056(2)	0.0553-0.0569
151Nd	60	91	150.923829(3)	12.44(7) min	3/2+
152Nd	60	92	151.924682(26)	11.4(2) min	0+
153Nd	60	93	152.927698(29)	31.6(10) s	(3/2)-
154Nd	60	94	153.92948(12)	25.9(2) s	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	3/2-#
156Nd	60	96	155.93502(22)	5.49(7) s	0+
156mNd	1432(5) keV			135 ns	5-
157Nd	60	97	156.93903(21)#	2# s [>300 ns]	5/2-#
158Nd	60	98	157.94160(43)#	700# ms [>300 ns]	0+
159Nd	60	99	158.94609(54)#	500# ms	7/2+#
160Nd	60	100	159.94909(64)#	300# ms	0+
161Nd	60	101	160.95388(75)#	200# ms	1/2-#

[edit] Notes

• Evaluated isotopic composition is for most but not all commercial samples.
• Geologically 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.

[edit] References

• Isotope masses from Ame2003 Atomic Mass Evaluation by G. Audi, A.H. Wapstra, C. Thibault, J. Blachot and O. Bersillon in Nuclear Physics A729 (2003).
• Isotopic compositions and standard atomic masses from Atomic weights of the elements. Review 2000 (IUPAC Technical Report). Pure Appl. Chem. Vol. 75, No. 6, pp. 683-800, (2003) and Atomic Weights Revised (2005).
• Half-life, spin, and isomer data selected from these sources. Editing notes on this article's talk page.
  • Audi, Bersillon, Blachot, Wapstra. The Nubase2003 evaluation of nuclear and decay properties, Nuc. Phys. A 729, pp. 3-128 (2003).
  • National Nuclear Data Center, Brookhaven National Laboratory. Information extracted from the NuDat 2.1 database (retrieved Sept. 2005).
  • David R. Lide (ed.), Norman E. Holden in CRC Handbook of Chemistry and Physics, 85th Edition, online version. CRC Press. Boca Raton, Florida (2005). Section 11, Table of the Isotopes.

Isotopes of praseodymium	Isotopes of neodymium	Isotopes of promethium
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