Naturally occurring

praseodymium Praseodymium is a chemical element with the symbol Pr and the atomic number 59. It is the third member of the lanthanide series and is considered to be one of the rare-earth metals. It is a soft, silvery, malleable and ductile metal, valued for i ...

(₅₉Pr) is composed of one stable

isotope Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers (mass numb ...

, ¹⁴¹Pr. Thirty-eight

radioisotope A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess nuclear energy, making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transferr ...

s have been characterized with the most stable being ¹⁴³Pr, with a

half-life Half-life (symbol ) is the time required for a quantity (of substance) to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable at ...

of 13.57 days and ¹⁴²Pr, with a half-life of 19.12 hours. All of the remaining

radioactive Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is consi ...

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 state A nuclear isomer is a metastable state of an atomic nucleus, in which one or more nucleons (protons or neutrons) occupy higher energy levels than in the ground state of the same nucleus. "Metastable" describes nuclei whose excited states have ...

s 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). The isotopes of praseodymium range in

atomic weight Relative atomic mass (symbol: ''A''; sometimes abbreviated RAM or r.a.m.), also known by the deprecated synonym atomic weight, is a dimensionless physical quantity defined as the ratio of the average mass of atoms of a chemical element in a giv ...

from 120.955 u (¹²¹Pr) to 158.955 u (¹⁵⁹Pr). The primary decay mode before the stable isotope, ¹⁴¹Pr, is

electron capture Electron capture (K-electron capture, also K-capture, or L-electron capture, L-capture) is a process in which the proton-rich nucleus of an electrically neutral atom absorbs an inner atomic electron, usually from the K or L electron shells. Thi ...

and the mode after is

beta decay In nuclear physics, beta decay (β-decay) is a type of radioactive decay in which a beta particle (fast energetic electron or positron) is emitted from an atomic nucleus, transforming the original nuclide to an isobar of that nuclide. For ...

. The primary decay products before ¹⁴¹Pr are element 58 (

cerium Cerium is a chemical element with the symbol Ce and atomic number 58. Cerium is a soft, ductile, and silvery-white metal that tarnishes when exposed to air. Cerium is the second element in the lanthanide series, and while it often shows the +3 ...

) isotopes and the primary products after are element 60 (

neodymium Neodymium is a chemical element with the symbol Nd and atomic number 60. It is the fourth member of the lanthanide series and is considered to be one of the rare-earth metals. It is a hard, slightly malleable, silvery metal that quickly tarnishe ...

) isotopes.

List of isotopes

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

References

* Isotope masses from: ** * Isotopic compositions and standard atomic masses from: ** ** * Half-life, spin, and isomer data selected from the following sources. ** ** ** {{Navbox element isotopes Praseodymium

Praseodymium Praseodymium is a chemical element with the symbol Pr and the atomic number 59. It is the third member of the lanthanide series and is considered to be one of the rare-earth metals. It is a soft, silvery, malleable and ductile metal, valued for i ...