Isotopes of praseodymium

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Naturally occurring praseodymium (Pr) 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 (t1/2 2.12 hours), 142mPr (t1/2 14.6 minutes) and 134mPr (t1/2 11 minutes).

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 minus decay. The primary decay products before 141Pr are element 58 (cerium) isotopes and the primary products after are element 60 (neodymium) isotopes.


Standard atomic mass: 140.90765(2) u

Table[edit]

nuclide
symbol
Z(p) N(n)  
isotopic mass (u)
 
half-life decay
mode(s)[1][n 1]
daughter
isotope(s)[n 2]
nuclear
spin
representative
isotopic
composition
(mole fraction)
range of natural
variation
(mole fraction)
excitation energy
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) ~11 min β+ 134Ce (5-)
134mPr 0(100)# keV 17(2) 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 3] 59 82 140.9076528(26) Stable[n 4] 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 3] 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. ^ Abbreviations:
    EC: Electron capture
    IT: Isomeric transition
  2. ^ Bold for stable isotopes, bold italics for nearly-stable isotopes (half-life longer than the age of the universe)
  3. ^ a b Fission product
  4. ^ Theoretically capable of spontaneous fission

Notes[edit]

  • 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[edit]

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


Isotopes of cerium Isotopes of praseodymium Isotopes of neodymium
Table of nuclides