Naturally occurring

barium Barium is a chemical element with the symbol Ba and atomic number 56. It is the fifth element in group 2 and is a soft, silvery alkaline earth metal. Because of its high chemical reactivity, barium is never found in nature as a free element. Th ...

(₅₆Ba) is a mix of six 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 num ...

s and one very long-lived radioactive primordial isotope, barium-130, identified as being unstable by geochemical means (from analysis of the presence of its daughter xenon-130 in rocks) in 2001. This nuclide decays by

double electron capture Double electron capture is a decay mode of an atomic nucleus. For a nuclide (''A'', ''Z'') with a number of nucleons ''A'' and atomic number ''Z'', double electron capture is only possible if the mass of the nuclide (''A'', ''Z''−2) is lower. ...

(absorbing two electrons and emitting two neutrinos), with a half-life of (0.5–2.7)×10²¹ years (about 10¹¹ times the age of the universe). There are a total of thirty-three known

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 in addition to ¹³⁰Ba. The longest-lived of these is ¹³³Ba, which has a half-life of 10.51 years. All other radioisotopes have half-lives shorter than two weeks. The longest-lived

isomer In chemistry, isomers are molecules or polyatomic ions with identical molecular formulae – that is, same number of atoms of each element – but distinct arrangements of atoms in space. Isomerism is existence or possibility of isomers. Is ...

is ^133mBa, which has a half-life of 38.9 hours. The shorter-lived ^137mBa (half-life 2.55 minutes) arises as the decay product of the common fission product

caesium-137 Caesium-137 (), cesium-137 (US), or radiocaesium, is a radioactive isotope of caesium that is formed as one of the more common fission products by the nuclear fission of uranium-235 and other fissionable isotopes in nuclear reactors and nucle ...

. Barium-114 is predicted to undergo

cluster decay Cluster decay, also named heavy particle radioactivity or heavy ion radioactivity, is a rare type of nuclear decay in which an atomic nucleus emits a small "cluster" of neutrons and protons, more than in an alpha particle, but less than a typic ...

, emitting a nucleus of stable ¹²C to produce ¹⁰²Sn. However this decay is not yet observed; the upper limit on the branching ratio of such decay is 0.0034%.

List of isotopes

, - , rowspan=4, ¹¹⁴Ba , rowspan=4 style="text-align:right" , 56 , rowspan=4 style="text-align:right" , 58 , rowspan=4, 113.95068(15) , rowspan=4, 530(230) ms
.43(+30−15) s, β⁺, p (99.59%) , ¹¹³Xe , rowspan=4, 0+ , rowspan=4, , rowspan=4, , - , α (.37%) , ¹¹⁰Xe , - , β⁺ (.04%) , ¹¹⁴Cs , - , CD (<.0034%)Cluster decay is predicted but had never been observed. , ¹⁰²Sn, ¹²C , - , rowspan=2, ¹¹⁵Ba , rowspan=2 style="text-align:right" , 56 , rowspan=2 style="text-align:right" , 59 , rowspan=2, 114.94737(64)# , rowspan=2, 0.45(5) s , β⁺ , ¹¹⁵Cs , rowspan=2, (5/2+)# , rowspan=2, , rowspan=2, , - , β⁺, p , ¹¹⁴Xe , - , rowspan=2, ¹¹⁶Ba , rowspan=2 style="text-align:right" , 56 , rowspan=2 style="text-align:right" , 60 , rowspan=2, 115.94138(43)# , rowspan=2, 1.3(2) s , β⁺ , ¹¹⁶Cs , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁺, p , ¹¹⁵Xe , - , rowspan=3, ¹¹⁷Ba , rowspan=3 style="text-align:right" , 56 , rowspan=3 style="text-align:right" , 61 , rowspan=3, 116.93850(32)# , rowspan=3, 1.75(7) s , β⁺ , ¹¹⁷Cs , rowspan=3, (3/2)(+#) , rowspan=3, , rowspan=3, , - , β⁺, α , ¹¹³I , - , β⁺, p , ¹¹⁶Xe , - , rowspan=2, ¹¹⁸Ba , rowspan=2 style="text-align:right" , 56 , rowspan=2 style="text-align:right" , 62 , rowspan=2, 117.93304(21)# , rowspan=2, 5.2(2) s , β⁺ , ¹¹⁸Cs , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁺, p , ¹¹⁷Xe , - , rowspan=2, ¹¹⁹Ba , rowspan=2 style="text-align:right" , 56 , rowspan=2 style="text-align:right" , 63 , rowspan=2, 118.93066(21) , rowspan=2, 5.4(3) s , β⁺ , ¹¹⁹Cs , rowspan=2, (5/2+) , rowspan=2, , rowspan=2, , - , β⁺, p , ¹¹⁸Xe , - , ¹²⁰Ba , style="text-align:right" , 56 , style="text-align:right" , 64 , 119.92604(32) , 24(2) s , β⁺ , ¹²⁰Cs , 0+ , , , - , rowspan=2, ¹²¹Ba , rowspan=2 style="text-align:right" , 56 , rowspan=2 style="text-align:right" , 65 , rowspan=2, 120.92405(15) , rowspan=2, 29.7(15) s , β⁺ (99.98%) , ¹²¹Cs , rowspan=2, 5/2(+) , rowspan=2, , rowspan=2, , - , β⁺, p (.02%) , ¹²⁰Xe , - , ¹²²Ba , style="text-align:right" , 56 , style="text-align:right" , 66 , 121.91990(3) , 1.95(15) min , β⁺ , ¹²²Cs , 0+ , , , - , ¹²³Ba , style="text-align:right" , 56 , style="text-align:right" , 67 , 122.918781(13) , 2.7(4) min , β⁺ , ¹²³Cs , 5/2(+) , , , - , ¹²⁴Ba , style="text-align:right" , 56 , style="text-align:right" , 68 , 123.915094(13) , 11.0(5) min , β⁺ , ¹²⁴Cs , 0+ , , , - , ¹²⁵Ba , style="text-align:right" , 56 , style="text-align:right" , 69 , 124.914473(12) , 3.5(4) min , β⁺ , ¹²⁵Cs , 1/2(+#) , , , - , ¹²⁶Ba , style="text-align:right" , 56 , style="text-align:right" , 70 , 125.911250(13) , 100(2) min , β⁺ , ¹²⁶Cs , 0+ , , , - , ¹²⁷Ba , style="text-align:right" , 56 , style="text-align:right" , 71 , 126.911094(12) , 12.7(4) min , β⁺ , ¹²⁷Cs , 1/2+ , , , - , style="text-indent:1em" , ^127mBa , colspan="3" style="text-indent:2em" , 80.33(12) keV , 1.9(2) s , IT , ¹²⁷Ba , 7/2− , , , - , ¹²⁸Ba , style="text-align:right" , 56 , style="text-align:right" , 72 , 127.908318(11) , 2.43(5) d , β⁺ , ¹²⁸Cs , 0+ , , , - , ¹²⁹Ba , style="text-align:right" , 56 , style="text-align:right" , 73 , 128.908679(12) , 2.23(11) h , β⁺ , ¹²⁹Cs , 1/2+ , , , - , rowspan=2 style="text-indent:1em" , ^129mBa , rowspan=2 colspan="3" style="text-indent:2em" , 8.42(6) keV , rowspan=2, 2.16(2) h , β⁺ , ¹²⁹Cs , rowspan=2, 7/2+# , rowspan=2, , rowspan=2, , - , IT , ¹²⁹Ba , - , ¹³⁰BaPrimordial radioisotope , style="text-align:right" , 56 , style="text-align:right" , 74 , 129.9063208(30) , 1.6(±1.1)×10²¹ y , Double EC , ¹³⁰Xe , 0+ , 0.00106(1) , , - , style="text-indent:1em" , ^130mBa , colspan="3" style="text-indent:2em" , 2475.12(18) keV , 9.54(14) ms , IT , ''¹³⁰Ba'' , 8− , , , - , ¹³¹Ba , style="text-align:right" , 56 , style="text-align:right" , 75 , 130.906941(3) , 11.50(6) d , β⁺ , ¹³¹Cs , 1/2+ , , , - , style="text-indent:1em" , ^131mBa , colspan="3" style="text-indent:2em" , 187.14(12) keV , 14.6(2) min , IT , ¹³¹Ba , 9/2− , , , - , ¹³²Ba , style="text-align:right" , 56 , style="text-align:right" , 76 , 131.9050613(11) , colspan=3 align=center,

Observationally Stable Stable nuclides are nuclides that are not radioactive and so (unlike radionuclides) do not spontaneously undergo radioactive decay. When such nuclides are referred to in relation to specific elements, they are usually termed stable isotopes. Th ...

Believed to undergo β⁺β⁺ decay to ¹³²Xe 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 ...

over 300×10¹⁸ years , 0+ , 0.00101(1) , , - , ¹³³Ba , style="text-align:right" , 56 , style="text-align:right" , 77 , 132.9060075(11) , 10.51(5) y , EC , ¹³³Cs , 1/2+ , , , - , rowspan=2 style="text-indent:1em" , ^133mBa , rowspan=2 colspan="3" style="text-indent:2em" , 288.247(9) keV , rowspan=2, 38.9(1) h , IT (99.99%) , ¹³³Ba , rowspan=2, 11/2− , rowspan=2, , rowspan=2, , - , EC (.0096%) , ¹³³Cs , - , ¹³⁴Ba , style="text-align:right" , 56 , style="text-align:right" , 78 , 133.9045084(4) , colspan=3 align=center, StableTheoretically capable of

spontaneous fission Spontaneous fission (SF) is a form of radioactive decay that is found only in very heavy chemical elements. The nuclear binding energy of the elements reaches its maximum at an atomic mass number of about 56 (e.g., iron-56); spontaneous breakd ...

, 0+ , 0.02417(18) , , - , ¹³⁵Ba , style="text-align:right" , 56 , style="text-align:right" , 79 , 134.9056886(4) , colspan=3 align=center, Stable , 3/2+ , 0.06592(12) , , - , style="text-indent:1em" , ^135mBa , colspan="3" style="text-indent:2em" , 268.22(2) keV , 28.7(2) h , IT , ¹³⁵Ba , 11/2− , , , - , ¹³⁶Ba , style="text-align:right" , 56 , style="text-align:right" , 80 , 135.9045759(4) , colspan=3 align=center, Stable , 0+ , 0.07854(24) , , - , style="text-indent:1em" , ^136mBa , colspan="3" style="text-indent:2em" , 2030.466(18) keV , 308.4(19) ms , IT , ¹³⁶Ba , 7− , , , - , ¹³⁷Ba , style="text-align:right" , 56 , style="text-align:right" , 81 , 136.9058274(5) , colspan=3 align=center, Stable , 3/2+ , 0.11232(24) , , - , style="text-indent:1em" , ^137m1Ba , colspan="3" style="text-indent:2em" , 661.659(3) keV , 2.552(1) min , IT , ¹³⁷Ba , 11/2− , , , - , style="text-indent:1em" , ^137m2Ba , colspan="3" style="text-indent:2em" , 2349.1(4) keV , 0.59(10) µs , , , (17/2−) , , , - , ¹³⁸Ba

Fission product Nuclear fission products are the atomic fragments left after a large atomic nucleus undergoes nuclear fission. Typically, a large nucleus like that of uranium fissions by splitting into two smaller nuclei, along with a few neutrons, the release ...

, style="text-align:right" , 56 , style="text-align:right" , 82 , 137.9052472(5) , colspan=3 align=center, Stable , 0+ , 0.71698(42) , , - , style="text-indent:1em" , ^138mBa , colspan="3" style="text-indent:2em" , 2090.54(6) keV , 800(100) ns , , , 6+ , , , - , ¹³⁹Ba , style="text-align:right" , 56 , style="text-align:right" , 83 , 138.9088413(5) , 83.06(28) min , β⁻ , ¹³⁹La , 7/2− , , , - , ¹⁴⁰Ba , style="text-align:right" , 56 , style="text-align:right" , 84 , 139.910605(9) , 12.752(3) d , β⁻ , ¹⁴⁰La , 0+ , , , - , ¹⁴¹Ba

, style="text-align:right" , 56 , style="text-align:right" , 85 , 140.914411(9) , 18.27(7) min , β⁻ , ¹⁴¹La , 3/2− , , , - , ¹⁴²Ba

, style="text-align:right" , 56 , style="text-align:right" , 86 , 141.916453(7) , 10.6(2) min , β⁻ , ¹⁴²La , 0+ , , , - , ¹⁴³Ba

, style="text-align:right" , 56 , style="text-align:right" , 87 , 142.920627(14) , 14.5(3) s , β⁻ , ¹⁴³La , 5/2− , , , - , ¹⁴⁴Ba

, style="text-align:right" , 56 , style="text-align:right" , 88 , 143.922953(14) , 11.5(2) s , β⁻ , ¹⁴⁴La , 0+ , , , - , ¹⁴⁵Ba , style="text-align:right" , 56 , style="text-align:right" , 89 , 144.92763(8) , 4.31(16) s , β⁻ , ¹⁴⁵La , 5/2− , , , - , rowspan=2, ¹⁴⁶Ba , rowspan=2 style="text-align:right" , 56 , rowspan=2 style="text-align:right" , 90 , rowspan=2, 145.93022(8) , rowspan=2, 2.22(7) s , β⁻ (99.98%) , ¹⁴⁶La , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁻, n (.02%) , ¹⁴⁵La , - , rowspan=2, ¹⁴⁷Ba , rowspan=2 style="text-align:right" , 56 , rowspan=2 style="text-align:right" , 91 , rowspan=2, 146.93495(22)# , rowspan=2, 0.893(1) s , β⁻ (99.94%) , ¹⁴⁷La , rowspan=2, (3/2+) , rowspan=2, , rowspan=2, , - , β⁻, n (.06%) , ¹⁴⁶La , - , rowspan=2, ¹⁴⁸Ba , rowspan=2 style="text-align:right" , 56 , rowspan=2 style="text-align:right" , 92 , rowspan=2, 147.93772(9) , rowspan=2, 0.612(17) s , β⁻ (99.6%) , ¹⁴⁸La , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁻, n (.4%) , ¹⁴⁷La , - , rowspan=2, ¹⁴⁹Ba , rowspan=2 style="text-align:right" , 56 , rowspan=2 style="text-align:right" , 93 , rowspan=2, 148.94258(21)# , rowspan=2, 344(7) ms , β⁻ (99.57%) , ¹⁴⁹La , rowspan=2, 3/2−# , rowspan=2, , rowspan=2, , - , β⁻, n (.43%) , ¹⁴⁸La , - , rowspan=2, ¹⁵⁰Ba , rowspan=2 style="text-align:right" , 56 , rowspan=2 style="text-align:right" , 94 , rowspan=2, 149.94568(43)# , rowspan=2, 300 ms , β⁻ , ¹⁵⁰La , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁻, n (rare) , ¹⁴⁹La , - , ¹⁵¹Ba , style="text-align:right" , 56 , style="text-align:right" , 95 , 150.95081(43)# , 200# ms 300 ns, β⁻ , ¹⁵¹La , 3/2−# , , , - , ¹⁵²Ba , style="text-align:right" , 56 , style="text-align:right" , 96 , 151.95427(54)# , 100# ms , β⁻ , ¹⁵²La , 0+ , , , - , ¹⁵³Ba , style="text-align:right" , 56 , style="text-align:right" , 97 , 152.95961(86)# , 80# ms , β⁻ , ¹⁵³La , 5/2−# , ,

References

* Isotope masses from: ** * Isotopic compositions and standard atomic masses from: ** ** * Half-life, spin, and isomer data selected from the following sources. ** ** ** * Half-life of ¹³⁰Ba from: ** ** {{Authority control Barium

Barium Barium is a chemical element with the symbol Ba and atomic number 56. It is the fifth element in group 2 and is a soft, silvery alkaline earth metal. Because of its high chemical reactivity, barium is never found in nature as a free element. Th ...

List of isotopes

See also

References