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 (t_1/2 2.12 hours), ^142mPr (t_1/2 14.6 minutes) and ^134mPr (t_1/2 11 minutes).

Isotopes of praseodymium (₅₉Pr)

Main isotopes[1] Decay 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[2] 140.91±0.01 (abridged)[3]
view talk edit

The isotopes of praseodymium range from ¹²¹Pr to 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)[4] [n 2][n 3]	Half-life[1] [n 4]	Decay mode[1] [n 5]	Daughter isotope [n 6][n 7]	Spin and parity[1] [n 8][n 4]	Isotopic abundance
	Excitation energy[n 4]
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[n 9]	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[n 10]	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[n 10]	59	84	142.9108226(19)	13.57(2) d	β−	143Nd	7/2+
144Pr[n 10]	59	85	143.9133107(29)	17.28(5) min	β−	144Nd	0−
144mPr[n 10]	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