Isotopes of praseodymium
Encyclopedia
Naturally occurring praseodymium
Praseodymium
Praseodymium is a chemical element that has the symbol Pr and atomic number 59. Praseodymium is a soft, silvery, malleable and ductile metal in the lanthanide group. It is too reactive to be found in native form, and when artificially prepared, it slowly develops a green oxide coating.The element...

(Pr) is composed of one stable isotope
Isotope
Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...

, 141Pr. Thirty-eight radioisotopes have been characterized with the most stable being 143Pr with a half-life
Half-life
Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...

 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 (t½ 2.12 hours), 142mPr (t½ 14.6 minutes) and 134mPr (t½ 11 minutes).

The isotopes of praseodymium range in atomic weight
Atomic weight
Atomic weight is a dimensionless physical quantity, the ratio of the average mass of atoms of an element to 1/12 of the mass of an atom of carbon-12...

 from 120.955 u
Atomic mass unit
The unified atomic mass unit or dalton is a unit that is used for indicating mass on an atomic or molecular scale. It is defined as one twelfth of the rest mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state, and has a value of...

 (121Pr) to 158.955 u (159Pr). The primary decay mode before the stable isotope, 141Pr, is electron capture
Electron capture
Electron capture is a process in which a proton-rich nuclide absorbs an inner atomic electron and simultaneously emits a neutrino...

 and the primary mode after is beta minus decay. The primary decay product
Decay product
In nuclear physics, a decay product is the remaining nuclide left over from radioactive decay. Radioactive decay often involves a sequence of steps...

s before 141Pr are element 58 (cerium
Cerium
Cerium is a chemical element with the symbol Ce and atomic number 58. It is a soft, silvery, ductile metal which easily oxidizes in air. Cerium was named after the dwarf planet . Cerium is the most abundant of the rare earth elements, making up about 0.0046% of the Earth's crust by weight...

) isotopes and the primary products after are element 60 (neodymium
Neodymium
Neodymium is a chemical element with the symbol Nd and atomic number 60. It is a soft silvery metal that tarnishes in air. Neodymium was discovered in 1885 by the Austrian chemist Carl Auer von Welsbach. It is present in significant quantities in the ore minerals monazite and bastnäsite...

) isotopes.


Standard atomic mass: 140.90765(2) u

Table

nuclide
symbol
Z(p
Proton
The proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number....

)
N(n
Neutron
The neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of...

)
 
isotopic mass (u)
 
half-life decay
mode(s)Abbreviations:
EC: Electron capture
Electron capture
Electron capture is a process in which a proton-rich nuclide absorbs an inner atomic electron and simultaneously emits a neutrino...


IT: Isomeric transition
Isomeric transition
An isomeric transition is a radioactive decay process that involves emission of a gamma ray from an atom where the nucleus is in an excited metastable state, referred to in its excited state, as a nuclear isomer....

daughter
isotope(s)Bold for stable isotopes, bold italics for nearly-stable isotopes (half-life longer than the age of the universe
Age of the universe
The age of the universe is the time elapsed since the Big Bang posited by the most widely accepted scientific model of cosmology. The best current estimate of the age of the universe is 13.75 ± 0.13 billion years within the Lambda-CDM concordance model...

)
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
Proton emission
Proton emission is a type of radioactive decay in which a proton is ejected from a nucleus. Proton emission can occur from high-lying excited states in a nucleus following a beta decay, in which case the process is known as beta-delayed proton emission, or can occur from the ground state of very...

120Ce (3/2-)
β+
Beta decay
In nuclear physics, beta decay is a type of radioactive decay in which a beta particle is emitted from an atom. There are two types of beta decay: beta minus and beta plus. In the case of beta decay that produces an electron emission, it is referred to as beta minus , while in the case of a...

 (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
Isomeric transition
An isomeric transition is a radioactive decay process that involves emission of a gamma ray from an atom where the nucleus is in an excited metastable state, referred to in its excited state, as a nuclear isomer....

 (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)-
141PrFission product
Fission product
Nuclear fission products are the atomic fragments left after a large atomic nucleus fissions. Typically, a large nucleus like that of uranium fissions by splitting into two smaller nuclei, along with a few neutrons and a large release of energy in the form of heat , gamma rays and neutrinos. The...

59 82 140.9076528(26) Observationally StableTheoretically capable of spontaneous fission
Spontaneous fission
Spontaneous fission is a form of radioactive decay characteristic of very heavy isotopes. Because the nuclear binding energy reaches a maximum at a nuclear mass greater than about 60 atomic mass units , spontaneous breakdown into smaller nuclei and single particles becomes possible at heavier masses...

5/2+ 1.0000
142Pr 59 83 141.9100448(26) 19.12(4) h β- (99.98%) 142Nd 2-
EC
Electron capture
Electron capture is a process in which a proton-rich nuclide absorbs an inner atomic electron and simultaneously emits a neutrino...

(.0164%)
142Ce
142mPr 3.694(3) keV 14.6(5) min IT 142Pr 5-
143Pr 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-#

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