Isotopes of barium

Naturally occurring barium (56Ba) is a mix of six stable isotopes 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 (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 radioisotopes 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 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.

Barium-114 is predicted to undergo cluster decay, 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|113.95072(11)
 * rowspan=4|460(125) ms
 * β+ (79%)
 * 114Cs
 * rowspan=4|0+
 * rowspan=4|
 * rowspan=4|
 * α (0.9%)
 * 110Xe
 * β+, p (20%)
 * 113Xe
 * CD (<.0034%)
 * 102Sn, 12C
 * rowspan=2|115Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 59
 * rowspan=2|114.94748(22)#
 * rowspan=2|0.45(5) s
 * β+
 * 115Cs
 * rowspan=2|5/2+#
 * rowspan=2|
 * rowspan=2|
 * β+, p (>15%)
 * 114Xe
 * rowspan=2|116Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 60
 * rowspan=2|115.94162(22)#
 * rowspan=2|1.3(2) s
 * β+ (97%)
 * 116Cs
 * rowspan=2|0+
 * rowspan=2|
 * rowspan=2|
 * β+, p (3%)
 * 115Xe
 * rowspan=3|117Ba
 * rowspan=3 style="text-align:right" | 56
 * rowspan=3 style="text-align:right" | 61
 * rowspan=3|116.93832(27)
 * rowspan=3|1.75(7) s
 * β+ (87%)
 * 117Cs
 * rowspan=3|(3/2+)
 * rowspan=3|
 * rowspan=3|
 * β+, p (13%)
 * 116Xe
 * β+, α (0.024%)
 * 113I
 * 118Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 62
 * 117.93323(22)#
 * 5.2(2) s
 * β+
 * 118Cs
 * 0+
 * 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+ (75%)
 * 119Cs
 * rowspan=2|(5/2+)
 * rowspan=2|
 * rowspan=2|
 * β+, p (25%)
 * 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 (0.02%)
 * 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+
 * style="text-indent:1em" | 123mBa
 * colspan="3" style="text-indent:2em" | 120.95(8) keV
 * 830(60) ns
 * IT
 * 123Ba
 * 1/2+#
 * 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
 * 124.914472(12)
 * 3.3(3) min
 * β+
 * 125Cs
 * 1/2+
 * style="text-indent:1em" | 125mBa
 * colspan="3" style="text-indent:2em" | 120(20)# keV
 * 2.76(14) μs
 * IT
 * 125Ba
 * (7/2−)
 * 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
 * 126.911091(12)
 * 12.7(4) min
 * β+
 * 127Cs
 * 1/2+
 * style="text-indent:1em" | 127mBa
 * colspan="3" style="text-indent:2em" | 80.32(11) keV
 * 1.93(7) s
 * IT
 * 127Ba
 * 7/2−
 * 128Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 72
 * 127.9083524(17)
 * 2.43(5) d
 * EC
 * 128Cs
 * 0+
 * 129Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 73
 * 128.908683(11)
 * 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|2.135(10) h
 * β+
 * 129Cs
 * rowspan=2|7/2+
 * rowspan=2|
 * rowspan=2|
 * IT
 * 129Ba
 * 130Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 74
 * 129.9063260(3)
 * ≈ 1×1021 y
 * 2EC?
 * 130Xe
 * 0+
 * 0.0011(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
 * 130.9069463(4)
 * 11.52(1) d
 * β+
 * 131Cs
 * 1/2+
 * style="text-indent:1em" | 131mBa
 * colspan="3" style="text-indent:2em" | 187.995(9) keV
 * 14.26(9) min
 * IT
 * 131Ba
 * 9/2−
 * 132Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 76
 * 131.9050612(11)
 * colspan=3 align=center|Observationally Stable
 * 0+
 * 0.0010(1)
 * 133Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 77
 * 132.9060074(11)
 * 10.5379(16) y
 * EC
 * 133Cs
 * 1/2+
 * rowspan=2 style="text-indent:1em" | 133mBa
 * rowspan=2 colspan="3" style="text-indent:2em" | 288.252(9) keV
 * rowspan=2|38.90(6) h
 * IT (99.99%)
 * 133Ba
 * rowspan=2|11/2−
 * rowspan=2|
 * rowspan=2|
 * EC (0.0104%)
 * 133Cs
 * 134Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 78
 * 133.90450825(27)
 * colspan=3 align=center|Stable
 * 0+
 * 0.0242(15)
 * style="text-indent:1em" | 134mBa
 * colspan="3" style="text-indent:2em" | 2957.2(5) keV
 * 2.61(13) μs
 * IT
 * 134Ba
 * 10+
 * 135Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 79
 * 134.90568845(26)
 * colspan=3 align=center|Stable
 * 3/2+
 * 0.0659(10)
 * style="text-indent:1em" | 135m1Ba
 * colspan="3" style="text-indent:2em" | 268.218(20) keV
 * 28.11(2) h
 * IT
 * 135Ba
 * 11/2−
 * style="text-indent:1em" | 135m2Ba
 * colspan="3" style="text-indent:2em" | 2388.0(5) keV
 * 1.06(4) ms
 * IT
 * 135Ba
 * (23/2+)
 * 136Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 80
 * 135.90457580(26)
 * colspan=3 align=center|Stable
 * 0+
 * 0.0785(24)
 * style="text-indent:1em" | 136m1Ba
 * colspan="3" style="text-indent:2em" | 2030.535(18) keV
 * 308.4(19) ms
 * IT
 * 136Ba
 * 7−
 * style="text-indent:1em" | 136m2Ba
 * colspan="3" style="text-indent:2em" | 3357.19(25) keV
 * 91(2) ns
 * IT
 * 136Ba
 * 10+
 * 137Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 81
 * 136.90582721(27)
 * colspan=3 align=center|Stable
 * 3/2+
 * 0.1123(23)
 * 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(5) keV
 * 589(20) ns
 * IT
 * 137Ba
 * (19/2−)
 * 138Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 82
 * 137.90524706(27)
 * colspan=3 align=center|Stable
 * 0+
 * 0.7170(29)
 * style="text-indent:1em" | 138mBa
 * colspan="3" style="text-indent:2em" | 2090.536(21) keV
 * 850(100) ns
 * IT
 * 138Ba
 * 6+
 * 139Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 83
 * 138.90884116(27)
 * 82.93(9) min
 * β−
 * 139La
 * 7/2−
 * 140Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 84
 * 139.910608(8)
 * 12.7534(21) d
 * β−
 * 140La
 * 0+
 * 141Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 85
 * 140.914404(6)
 * 18.27(7) min
 * β−
 * 141La
 * 3/2−
 * 142Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 86
 * 141.916433(6)
 * 10.6(2) min
 * β−
 * 142La
 * 0+
 * 143Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 87
 * 142.920625(7)
 * 14.5(3) s
 * β−
 * 143La
 * 5/2−
 * 144Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 88
 * 143.922955(8)
 * 11.73(8) s
 * β−
 * 144La
 * 0+
 * 145Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 89
 * 144.927518(9)
 * 4.31(16) s
 * β−
 * 145La
 * 5/2−
 * 146Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 90
 * 145.9303632(19)
 * 2.15(4) s
 * β−
 * 146La
 * 0+
 * rowspan=2|147Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 91
 * rowspan=2|146.935304(21)
 * rowspan=2|893(1) ms
 * β− (99.93%)
 * 147La
 * rowspan=2|5/2−
 * rowspan=2|
 * rowspan=2|
 * β−, n (0.07%)
 * 146La
 * rowspan=2|148Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 92
 * rowspan=2| 147.9382230(16)
 * rowspan=2|620(5) ms
 * β− (99.6%)
 * 148La
 * rowspan=2|0+
 * rowspan=2|
 * rowspan=2|
 * β−, n (0.4%)
 * 147La
 * rowspan=2|149Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 93
 * rowspan=2|148.9432840(27)
 * rowspan=2|349(4) ms
 * β− (96.1%)
 * 149La
 * rowspan=2|3/2−#
 * rowspan=2|
 * rowspan=2|
 * β−, n (3.9%)
 * 148La
 * rowspan=2|150Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 94
 * rowspan=2| 149.946441(6)
 * rowspan=2|258(5) ms
 * β− (99.0%)
 * 150La
 * rowspan=2|0+
 * rowspan=2|
 * rowspan=2|
 * β−, n (1.0%)
 * 149La
 * rowspan=2|151Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 95
 * rowspan=2|150.95176(43)#
 * rowspan=2|167(5) ms
 * β−
 * 151La
 * rowspan=2|3/2−#
 * rowspan=2|
 * rowspan=2|
 * β−, n?
 * 150La
 * rowspan=2|152Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 96
 * rowspan=2|151.95533(43)#
 * rowspan=2|139(8) ms
 * β−
 * 152La
 * rowspan=2|0+
 * rowspan=2|
 * rowspan=2|
 * β−, n?
 * 151La
 * rowspan=3|153Ba
 * rowspan=3 style="text-align:right" | 56
 * rowspan=3 style="text-align:right" | 97
 * rowspan=3|152.96085(43)#
 * rowspan=3|113(39) ms
 * β−
 * 153La
 * rowspan=3|5/2−#
 * rowspan=3|
 * rowspan=3|
 * β−, n?
 * 152La
 * β−, 2n?
 * 151La
 * 154Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 98
 * 153.96466(54)#
 * 53(48) ms
 * β−
 * 154La
 * 0+
 * β−
 * 143La
 * 5/2−
 * 144Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 88
 * 143.922955(8)
 * 11.73(8) s
 * β−
 * 144La
 * 0+
 * 145Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 89
 * 144.927518(9)
 * 4.31(16) s
 * β−
 * 145La
 * 5/2−
 * 146Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 90
 * 145.9303632(19)
 * 2.15(4) s
 * β−
 * 146La
 * 0+
 * rowspan=2|147Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 91
 * rowspan=2|146.935304(21)
 * rowspan=2|893(1) ms
 * β− (99.93%)
 * 147La
 * rowspan=2|5/2−
 * rowspan=2|
 * rowspan=2|
 * β−, n (0.07%)
 * 146La
 * rowspan=2|148Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 92
 * rowspan=2| 147.9382230(16)
 * rowspan=2|620(5) ms
 * β− (99.6%)
 * 148La
 * rowspan=2|0+
 * rowspan=2|
 * rowspan=2|
 * β−, n (0.4%)
 * 147La
 * rowspan=2|149Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 93
 * rowspan=2|148.9432840(27)
 * rowspan=2|349(4) ms
 * β− (96.1%)
 * 149La
 * rowspan=2|3/2−#
 * rowspan=2|
 * rowspan=2|
 * β−, n (3.9%)
 * 148La
 * rowspan=2|150Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 94
 * rowspan=2| 149.946441(6)
 * rowspan=2|258(5) ms
 * β− (99.0%)
 * 150La
 * rowspan=2|0+
 * rowspan=2|
 * rowspan=2|
 * β−, n (1.0%)
 * 149La
 * rowspan=2|151Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 95
 * rowspan=2|150.95176(43)#
 * rowspan=2|167(5) ms
 * β−
 * 151La
 * rowspan=2|3/2−#
 * rowspan=2|
 * rowspan=2|
 * β−, n?
 * 150La
 * rowspan=2|152Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 96
 * rowspan=2|151.95533(43)#
 * rowspan=2|139(8) ms
 * β−
 * 152La
 * rowspan=2|0+
 * rowspan=2|
 * rowspan=2|
 * β−, n?
 * 151La
 * rowspan=3|153Ba
 * rowspan=3 style="text-align:right" | 56
 * rowspan=3 style="text-align:right" | 97
 * rowspan=3|152.96085(43)#
 * rowspan=3|113(39) ms
 * β−
 * 153La
 * rowspan=3|5/2−#
 * rowspan=3|
 * rowspan=3|
 * β−, n?
 * 152La
 * β−, 2n?
 * 151La
 * 154Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 98
 * 153.96466(54)#
 * 53(48) ms
 * β−
 * 154La
 * 0+
 * 151La
 * rowspan=3|153Ba
 * rowspan=3 style="text-align:right" | 56
 * rowspan=3 style="text-align:right" | 97
 * rowspan=3|152.96085(43)#
 * rowspan=3|113(39) ms
 * β−
 * 153La
 * rowspan=3|5/2−#
 * rowspan=3|
 * rowspan=3|
 * β−, n?
 * 152La
 * β−, 2n?
 * 151La
 * 154Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 98
 * 153.96466(54)#
 * 53(48) ms
 * β−
 * 154La
 * 0+
 * 53(48) ms
 * β−
 * 154La
 * 0+