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 six 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 (2.12 hours), ^142mPr (14.6 minutes) and ^134mPr (~11 minutes).

Isotopes of praseodymium (₅₉Pr)

Main isotopes Decay Isotope abun­dance half-life (t1/2) mode pro­duct ^141Pr 100% stable ^142Pr synth 19.12 h β^− ^142Nd ε ^142Ce ^143Pr synth 13.57 d β^− ^143Nd
Standard atomic weight Ar°(Pr)
	140.90766±0.00001 140.91±0.01 (abridged)
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The known isotopes of praseodymium range from ¹²¹Pr to ¹⁵⁹Pr. The primary decay mode of isotopes lighter than ¹⁴¹Pr is positron emission or electron capture to isotopes of cerium, while that of heavier isotopes is beta decay to isotopes of neodymium.

List of isotopes

Nuclide	Z	N	Isotopic mass (Da)	Half-life	Decay mode	Daughter isotope	Spin and parity	Isotopic abundance
	Excitation energy
^121Pr	59	62	120.95539(54)#	12(5) ms	p	^120Ce	(3/2)(+#)
^124Pr	59	65	123.94294(43)#	1.2(2) s	β^+	^124Ce
					β^+, p (?%)	^123La
^125Pr	59	66	124.93766(32)#	3.3(7) s	β^+	^125Ce	3/2+#
^126Pr	59	67	125.93524(21)#	3.12(18) s	β^+	^126Ce	(4, 5)
					β^+, p (?%)	^125La
^127Pr	59	68	126.93071(21)#	4.2(3) s	β^+	^127Ce	3/2+#
^127mPr	600(200)# keV			2# μs			(11/2−)
^128Pr	59	69	127.928791(32)	2.85(9) s	β^+	^128Ce	(3+)
					β^+, p (?%)	^127La
^129Pr	59	70	128.925095(32)	30(4) s	β^+	^129Ce	(3/2+)
^129mPr	382.57(24) keV			26(11)# μs	IT	^129Pr	(11/2−)
^130Pr	59	71	129.923590(69)	40.0(4) s	β^+	^130Ce	(6, 7)(+#)
^130mPr	100(100)# keV			10# s			2+#
^131Pr	59	72	130.920235(50)	1.50(3) min	β^+	^131Ce	(3/2+)
^131mPr	152.4(3) keV			5.73(20) s	IT (96.4%)	^131Pr	(11/2−)
					β^+ (3.6%)	^131Ce
^132Pr	59	73	131.919240(31)	1.49(11) min	β^+	^132Ce	(2+)
^132m1Pr	30(30)# keV			1# s			(5+)
^132m2Pr	250(30)# keV			2.46(4) μs	IT	^132Pr	(8+)
^132m3Pr	300(30)# keV			486(70) ns	IT	^132Pr	(8−)
^133Pr	59	74	132.916331(13)	6.5(3) min	β^+	^133Ce	5/2+
^133mPr	192.12(14) keV			1.1(2) μs	IT	^133Pr	(11/2−)
^134Pr	59	75	133.915697(22)	17(2) min	β^+	^134Ce	2−
^134mPr	67.7(4) keV			~11 min	β^+	^134Ce	6−
^135Pr	59	76	134.913112(13)	24(1) min	β^+	^135Ce	3/2+
^135mPr	358.06(6) keV			105(10) μs	IT	^135Pr	(11/2−)
^136Pr	59	77	135.912677(12)	13.1(1) min	β^+	^136Ce	2+
^137Pr	59	78	136.9106792(87)	1.28(3) h	β^+	^137Ce	5/2+
^137mPr	561.22(23) keV			2.66(7) μs	IT	^137Pr	11/2−
^138Pr	59	79	137.910757(11)	1.45(5) min	β^+	^138Ce	1+
^138mPr	350(19) keV			2.12(4) h	β^+	^138Ce	7−
^139Pr	59	80	138.9089327(39)	4.41(4) h	β^+	^139Ce	5/2+
^140Pr	59	81	139.9090856(66)	3.39(1) min	EC (51.3%)	^140Ce	1+
					β^+ (48.7%)
^140m1Pr	127.8(3) keV			0.35(2) μs	IT	^140Pr	5+
^140m2Pr	763.7(5) keV			3.05(20) μs	IT	^140Pr	(7)−
^141Pr	59	82	140.9076596(16)	Stable			5/2+	1.0000
^142Pr	59	83	141.9100516(16)	19.12(4) h	β^− (99.98%)	^142Nd	2−
					EC (0.0164%)	^142Ce
^142mPr	3.694(3) keV			14.6(5) min	IT	^142Pr	5−
^143Pr	59	84	142.9108226(19)	13.57(2) d	β^−	^143Nd	7/2+
^144Pr	59	85	143.9133107(29)	17.28(5) min	β^−	^144Nd	0−
^144mPr	59.03(3) keV			7.2(3) min	IT (~99.93%)	^144Pr	3−
					β^− (~0.07%)	^144Nd
^145Pr	59	86	144.9145180(77)	5.984(10) h	β^−	^145Nd	7/2+
^146Pr	59	87	145.917688(37)	24.09(10) min	β^−	^146Nd	(2−)
^147Pr	59	88	146.919007(17)	13.39(4) min	β^−	^147Nd	3/2+
^148Pr	59	89	147.922130(16)	2.29(2) min	β^−	^148Nd	1−
^148mPr	76.80(20) keV			2.01(7) min	β^− (64%)	^148Nd	(4)
					IT (36%)	^148Pr
^149Pr	59	90	148.923736(11)	2.26(7) min	β^−	^149Nd	(5/2+)
^150Pr	59	91	149.9266764(97)	6.19(16) s	β^−	^150Nd	1−
^151Pr	59	92	150.928309(13)	18.90(7) s	β^−	^151Nd	(3/2−)
^151mPr	35.10(10) keV			50(8) μs	IT	^151Pr	(7/2+)
^152Pr	59	93	151.931553(20)	3.57(11) s	β^−	^152Nd	4+
^152mPr	115.1(3) keV			4.16(10) μs	IT	^152Pr	(1+)
^153Pr	59	94	152.933904(13)	4.28(11) s	β^−	^153Nd	3/2−#
^154Pr	59	95	153.93789(11)	2.30(9) s	β^−	^154Nd	(3+)
^155Pr	59	96	154.940509(18)	1.47(3) s	β^−	^155Nd	3/2−#
^156Pr	59	97	155.9447669(11)	444(6) ms	β^−	^156Nd	1+#
^157Pr	59	98	156.9480031(34)	307(21) ms	β^−	^157Nd	3/2−#
^158Pr	59	99	157.95260(32)#	181(14) ms	β^−	^158Nd	5−#
^159Pr	59	100	158.95623(43)#	134(43) ms	β^−	^159Nd	3/2−#
^160Pr	59	101	159.96114(43)#	170(140) ms	β^−	^160Nd	1+#
^161Pr	59	102	160.96512(54)#	90# ms [>550 ns]			3/2−#
This table header & footer: view

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. Order of ground state and isomer is uncertain.
10. Fission product

See also

Daughter products other than praseodymium

• Isotopes of neodymium
• Isotopes of cerium
• Isotopes of lanthanum