Isotopes of praseodymium

Naturally occurring praseodymium (₅₉Pr) is composed of one stable isotope, ¹⁴¹Pr. Thirty-eight radioisotopes have been characterized with the most stable being ¹⁴³Pr, with a half-life of 13.57 days and ¹⁴²Pr, with a half-life of 19.12 hours. All of the remaining radioactive isotopes have half-lives that are less than 5.985 hours and the majority of these have half-lives that are less than 33 seconds. This element also has 15 meta states with the most stable being ^138mPr (t_1/2 2.12 hours), ^142mPr (t_1/2 14.6 minutes) and ^134mPr (t_1/2 11 minutes).

Main isotopes of praseodymium (₅₉Pr)

Iso­tope Decay abun­dance half-life (t1/2) mode pro­duct ^141Pr 100% stable ^142Pr syn 19.12 h β^− ^142Nd ε ^142Ce ^143Pr syn 13.57 d β^− ^143Nd
Standard atomic weight Ar, standard(Pr)	140.90766(2)[1]

The isotopes of praseodymium range in atomic weight from 120.955 u (¹²¹Pr) to 158.955 u (¹⁵⁹Pr). The primary decay mode before the stable isotope, ¹⁴¹Pr, is electron capture and the mode after is beta decay. The primary decay products before ¹⁴¹Pr are element 58 (cerium) isotopes and the primary products after are element 60 (neodymium) isotopes.

List of isotopes

Nuclide [n 1]	Z	N	Isotopic mass (Da) [n 2][n 3]	Half-life [n 4]	Decay mode [n 5]	Daughter isotope [n 6][n 7]	Spin and parity [n 8][n 4]	Natural abundance (mole fraction)
	Excitation energy[n 4]							Normal proportion	Range of variation
^121Pr	59	62	120.95536(75)#	600(300) ms	p	^120Ce	(3/2−)
					β^+ (rare)	^121Ce
					β^+, p (rare)	^120La
^122Pr	59	63	121.95181(54)#	500# ms	β^+	^122Ce
^123Pr	59	64	122.94596(64)#	800# ms	β^+	^123Ce	3/2+#
^124Pr	59	65	123.94296(64)#	1.2(2) s	β^+	^124Ce
					β^+, p (rare)	^123La
^125Pr	59	66	124.93783(43)#	3.3(7) s	β^+	^125Ce	3/2+#
					β^+, p (rare)	^124La
^126Pr	59	67	125.93531(21)#	3.12(18) s	β^+	^126Ce	(4, 5, 6)
					β^+, p (rare)	^125La
^127Pr	59	68	126.93083(21)#	4.2(3) s	β^+	^127Ce	3/2+#
^127mPr	600(200)# keV			50# ms			11/2−
^128Pr	59	69	127.92879(3)	2.84(9) s	β^+	^128Ce	(3+)
					β^+, p (rare)	^127La
^129Pr	59	70	128.92510(3)	32(3) s	β^+	^129Ce	(11/2−)
^129mPr	382.7(5) keV			1# ms	β^+	^129Ce	(11/2−)
^130Pr	59	71	129.92359(7)	40.0(4) s	β^+	^130Ce	(6, 7)(+#)
^130mPr	100(100)# keV			10# s			2+#
^131Pr	59	72	130.92026(6)	1.50(3) min	β^+	^131Ce	(3/2+)
^131mPr	152.4(2) keV			5.7(2) s	IT (96.4%)	^131Pr	(11/2−)
					β^+ (3.59%)	^131Ce
^132Pr	59	73	131.91926(6)	1.49(11) min	β^+	^132Ce	(2+)
^132mPr	0(100)# keV			20# s	β^+	^132Ce	(5+)
^133Pr	59	74	132.916331(13)	6.5(3) min	β^+	^133Ce	(3/2+)
^133mPr	192.05(14) keV			1.1(2) μs			(11/2−)
^134Pr	59	75	133.91571(4)	17(2) min	β^+	^134Ce	(5−)
^134mPr	0(100)# keV			~11 min	β^+	^134Ce	2−
^135Pr	59	76	134.913112(13)	24(2) min	β^+	^135Ce	3/2(+)
^135mPr	358.06(6) keV			105(10) μs			(11/2−)
^136Pr	59	77	135.912692(13)	13.1(1) min	β^+	^136Ce	2+
^137Pr	59	78	136.910705(13)	1.28(3) h	β^+	^137Ce	5/2+
^137mPr	561.22(23) keV			2.66(7) μs			11/2−
^138Pr	59	79	137.910755(15)	1.45(5) min	β^+	^138Ce	1+
^138mPr	348(23) keV			2.12(4) h	β^+	^138Ce	7−
^139Pr	59	80	138.908938(8)	4.41(4) h	β^+	^139Ce	5/2+
^140Pr	59	81	139.909076(7)	3.39(1) min	β^+	^140Ce	1+
^140m1Pr	127.5(3) keV			0.35(2) μs			5+
^140m2Pr	763.3(7) keV			3.05(20) μs			(8)−
^141Pr[n 9]	59	82	140.9076528(26)	Stable			5/2+	1.0000
^142Pr	59	83	141.9100448(26)	19.12(4) h	β^− (99.98%)	^142Nd	2−
					EC (.0164%)	^142Ce
^142mPr	3.694(3) keV			14.6(5) min	IT	^142Pr	5−
^143Pr[n 9]	59	84	142.9108169(28)	13.57(2) d	β^−	^143Nd	7/2+
^144Pr	59	85	143.913305(4)	17.28(5) min	β^−	^144Nd	0−
^144mPr	59.03(3) keV			7.2(3) min	IT (99.93%)	^144Pr	3−
					β^− (.07%)	^144Nd
^145Pr	59	86	144.914512(8)	5.984(10) h	β^−	^145Nd	7/2+
^146Pr	59	87	145.91764(7)	24.15(18) min	β^−	^146Nd	(2)−
^147Pr	59	88	146.918996(25)	13.4(4) min	β^−	^147Nd	(3/2+)
^148Pr	59	89	147.922135(28)	2.29(2) min	β^−	^148Nd	1−
^148mPr	50(30)# keV			2.01(7) min	β^−	^148Nd	(4)
^149Pr	59	90	148.92372(9)	2.26(7) min	β^−	^149Nd	(5/2+)
^150Pr	59	91	149.926673(28)	6.19(16) s	β^−	^150Nd	(1)−
^151Pr	59	92	150.928319(25)	18.90(7) s	β^−	^151Nd	(3/2)(−#)
^152Pr	59	93	151.93150(13)	3.63(12) s	β^−	^152Nd	4+
^153Pr	59	94	152.93384(11)	4.28(11) s	β^−	^153Nd	5/2−#
^154Pr	59	95	153.93752(16)	2.3(1) s	β^−	^154Nd	(3+, 2+)
^155Pr	59	96	154.94012(32)#	1# s [>300 ns]	β^−	^155Nd	5/2−#
^156Pr	59	97	155.94427(43)#	500# ms [>300 ns]	β^−	^156Nd
^157Pr	59	98	156.94743(43)#	300# ms	β^−	^157Nd	5/2−#
^158Pr	59	99	157.95198(64)#	200# ms	β^−	^158Nd
^159Pr	59	100	158.95550(75)#	100# ms	β^−	^159Nd	5/2−#

1. ^mPr – Excited nuclear isomer.
2. ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
3. # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
4. # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
5. Modes of decay:

   EC:	Electron capture
   IT:	Isomeric transition
   p:	Proton emission

6. Bold italics symbol as daughter – Daughter product is nearly stable.
7. Bold symbol as daughter – Daughter product is stable.
8. ( ) spin value – Indicates spin with weak assignment arguments.
9. Fission product

References

1. Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.

• 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. Lay summary.
• 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.