Isotopes of cerium
Encyclopedia
Naturally occurring 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...

(Ce) is composed of 4 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...

s: 136Ce, 138Ce, 140Ce, and 142Ce with 140Ce being the most abundant (88.48% natural abundance
Natural abundance
In chemistry, natural abundance refers to the abundance of isotopes of a chemical element as naturally found on a planet. The relative atomic mass of these isotopes is the atomic weight listed for the element in the periodic table...

); 136Ce, 138Ce, and 142Ce are predicted to undergo double beta decay but this process has never been observed. 35 radioisotopes have been characterized with the most stable being 144Ce with a half-life of 284.893 days, 139Ce with a half-life of 137.640 days, and 141Ce with a half-life of 32.501 days. All of the remaining radioactive isotopes have half-lives that are less than 4 days and the majority of these have half-lives that are less than 10 minutes. This element also has 10 meta states.

The isotopes of cerium 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 119 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...

 (119Ce) to 157 u (157Ce).

Standard atomic mass: 140.116(1) 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
nuclear
spin
representative
isotopic
composition
(mole fraction)
range of natural
variation
(mole fraction)
excitation energy
119Ce 58 61 118.95276(64)# 200# ms 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...

119La 5/2+#
120Ce 58 62 119.94664(75)# 250# ms β+ 120La 0+
121Ce 58 63 120.94342(54)# 1.1(1) s β+ 121La (5/2)(+#)
122Ce 58 64 121.93791(43)# 2# s β+ 122La 0+
β+, 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...

121Ba
123Ce 58 65 122.93540(32)# 3.8(2) s β+ 123La (5/2)(+#)
β+, p 122Ba
124Ce 58 66 123.93041(32)# 9.1(12) s β+ 124La 0+
125Ce 58 67 124.92844(21)# 9.3(3) s β+ 125La (7/2-)
β+, p 124Ba
126Ce 58 68 125.92397(3) 51.0(3) s β+ 126La 0+
127Ce 58 69 126.92273(6) 29(2) s β+ 127La 5/2+#
128Ce 58 70 127.91891(3) 3.93(2) min β+ 128La 0+
129Ce 58 71 128.91810(3) 3.5(3) min β+ 129La (5/2+)
130Ce 58 72 129.91474(3) 22.9(5) min β+ 130La 0+
130mCe 2453.6(3) keV 100(8) ns (7-)
131Ce 58 73 130.91442(4) 10.2(3) min β+ 131La (7/2+)
131mCe 61.8(1) keV 5.0(10) min β+ 131La (1/2+)
132Ce 58 74 131.911460(22) 3.51(11) h β+ 132La 0+
132mCe 2340.8(5) keV 9.4(3) ms 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....

132Ce (8-)
133Ce 58 75 132.911515(18) 97(4) min β+ 133La 1/2+
133mCe 37.1(8) keV 4.9(4) h β+ 133La 9/2-
134Ce 58 76 133.908925(22) 3.16(4) d EC
Electron capture
Electron capture is a process in which a proton-rich nuclide absorbs an inner atomic electron and simultaneously emits a neutrino...

134La 0+
135Ce 58 77 134.909151(12) 17.7(3) h β+ 135La 1/2(+)
135mCe 445.8(2) keV 20(1) s IT 135Ce (11/2-)
136Ce 58 78 135.907172(14) Observationally StableTheorized to undergo β+β+ decay to 136Ba 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...

 over 38×1015 years
0+ 0.00185(2) 0.00185-0.00186
136mCe 3095.5(4) keV 2.2(2) µs 10+
137Ce 58 79 136.907806(14) 9.0(3) h β+ 137La 3/2+
137mCe 254.29(5) keV 34.4(3) h IT (99.22%) 137Ce 11/2-
β+ (.779%) 137La
138Ce 58 80 137.905991(11) Observationally StableTheorized to undergo β+β+ decay to 138Ba with a half-life over 150×1012 years 0+ 0.00251(2) 0.00251-0.00254
138mCe 2129.17(12) keV 8.65(20) ms IT 138Ce 7-
139Ce 58 81 138.906653(8) 137.641(20) d EC 139La 3/2+
139mCe 754.24(8) keV 56.54(13) s IT 139Ce 11/2-
140CeFission 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...

58 82 139.9054387(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...

0+ 0.88450(51) 0.88446-0.88449
140mCe 2107.85(3) keV 7.3(15) µs 6+
141Ce 58 83 140.9082763(26) 32.508(13) d β- 141Pr 7/2-
142Ce 58 84 141.909244(3) Observationally StableTheorized to undergo β-β- decay to 142Nd with a half-life over 50×1015 years 0+ 0.11114(51) 0.11114-0.11114
143Ce 58 85 142.912386(3) 33.039(6) h β- 143Pr 3/2-
144Ce 58 86 143.913647(4) 284.91(5) d β- 144mPr 0+
145Ce 58 87 144.91723(4) 3.01(6) min β- 145Pr (3/2-)
146Ce 58 88 145.91876(7) 13.52(13) min β- 146Pr 0+
147Ce 58 89 146.92267(3) 56.4(10) s β- 147Pr (5/2-)
148Ce 58 90 147.92443(3) 56(1) s β- 148Pr 0+
149Ce 58 91 148.9284(1) 5.3(2) s β- 149Pr (3/2-)#
150Ce 58 92 149.93041(5) 4.0(6) s β- 150Pr 0+
151Ce 58 93 150.93398(11) 1.02(6) s β- 151Pr 3/2-#
152Ce 58 94 151.93654(21)# 1.4(2) s β- 152Pr 0+
153Ce 58 95 152.94058(43)# 500# ms [>300 ns] β- 153Pr 3/2-#
154Ce 58 96 153.94342(54)# 300# ms [>300 ns] β- 154Pr 0+
155Ce 58 97 154.94804(64)# 200# ms [>300 ns] β- 155Pr 5/2-#
156Ce 58 98 155.95126(64)# 150# ms β- 156Pr 0+
157Ce 58 99 156.95634(75)# 50# ms β- 157Pr 7/2+#

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