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, presumably decaying by double electron capture with a half-life of (0.5–2.7)×10²¹ years (about 10¹¹ times the age of the universe). The two measurements are discordant; the above reflects the total range, the value in the table below is a crude average.

With the total range of mass numbers known 114 to 154, there are thirty-three known radioisotopes in addition to ¹³⁰Ba. The longest-lived of these is ¹³³Ba, which has a half-life of 10.538 years; all others have half-lives shorter than two weeks. The longest-lived isomers are ^133mBa at 38.90 hours and ^135m1Ba at 28.11 hours. The analogous ^137m1Ba (half-life 2.552 minutes) occurs in the decay of the common fission product caesium-137.

Barium-114 is theorized to undergo cluster decay, emitting a nucleus of stable ¹²C to produce ¹⁰²Sn. This decay has not been observed, with only an upper limit on the branching ratio of such decay (0.0034%).

List of isotopes

|-id=Barium-114 | 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)&nbsp;ms | β⁺ (79%) | ¹¹⁴Cs | rowspan=4|0+ | rowspan=4| | rowspan=4| |- | α (0.9%) | ¹¹⁰Xe |- | β⁺, p (20%) | ¹¹³Xe |- | CD (<.0034%) | ¹⁰²Sn, ¹²C |-id=Barium-115 | 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)&nbsp;s | β⁺ | ¹¹⁵Cs | rowspan=2|5/2+# | rowspan=2| | rowspan=2| |- | β⁺, p (>15%) | ¹¹⁴Xe |-id=Barium-116 | 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)&nbsp;s | β⁺ (97%) | ¹¹⁶Cs | rowspan=2|0+ | rowspan=2| | rowspan=2| |- | β⁺, p (3%) | ¹¹⁵Xe |-id=Barium-117 | 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)&nbsp;s | β⁺ (87%) | ¹¹⁷Cs | rowspan=3|(3/2+) | rowspan=3| | rowspan=3| |- | β⁺, p (13%) | ¹¹⁶Xe |- | β⁺, α (0.024%) | ¹¹³I |-id=Barium-118 | ¹¹⁸Ba | style="text-align:right" | 56 | style="text-align:right" | 62 | 117.93323(22)# | 5.2(2)&nbsp;s | β⁺ | ¹¹⁸Cs | 0+ | | |-id=Barium-119 | 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)&nbsp;s | β⁺ (75%) | ¹¹⁹Cs | rowspan=2|(3/2+) | rowspan=2| | rowspan=2| |- | β⁺, p (25%) | ¹¹⁸Xe |-id=Barium-119m | style="text-indent:1em" | ^119mBa | colspan="3" style="text-indent:2em" | 66.0&nbsp;keV | 360(20)&nbsp;ns | IT | ¹¹⁹Ba | (5/2−) | | |-id=Barium-120 | ¹²⁰Ba | style="text-align:right" | 56 | style="text-align:right" | 64 | 119.92604(32) | 24(2)&nbsp;s | β⁺ | ¹²⁰Cs | 0+ | | |-id=Barium-121 | 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)&nbsp;s | β⁺ (99.98%) | ¹²¹Cs | rowspan=2|5/2+ | rowspan=2| | rowspan=2| |- | β⁺, p (0.02%) | ¹²⁰Xe |-id=Barium-122 | ¹²²Ba | style="text-align:right" | 56 | style="text-align:right" | 66 | 121.91990(3) | 1.95(15)&nbsp;min | β⁺ | ¹²²Cs | 0+ | | |-id=Barium-123 | ¹²³Ba | style="text-align:right" | 56 | style="text-align:right" | 67 | 122.918781(13) | 2.7(4)&nbsp;min | β⁺ | ¹²³Cs | 5/2+ | | |-id=Barium-123m | style="text-indent:1em" | ^123mBa | colspan="3" style="text-indent:2em" | 120.95(8)&nbsp;keV | 830(60)&nbsp;ns | IT | ¹²³Ba | 1/2+# | | |-id=Barium-124 | ¹²⁴Ba | style="text-align:right" | 56 | style="text-align:right" | 68 | 123.915094(13) | 11.0(5)&nbsp;min | β⁺ | ¹²⁴Cs | 0+ | | |-id=Barium-125 | ¹²⁵Ba | style="text-align:right" | 56 | style="text-align:right" | 69 | 124.914472(12) | 3.3(3)&nbsp;min | β⁺ | ¹²⁵Cs | 1/2+ | | |-id=Barium-125m | style="text-indent:1em" | ^125mBa | colspan="3" style="text-indent:2em" | 120(20)#&nbsp;keV | 2.76(14)&nbsp;μs | IT | ¹²⁵Ba | (7/2−) | | |-id=Barium-126 | ¹²⁶Ba | style="text-align:right" | 56 | style="text-align:right" | 70 | 125.911250(13) | 100(2)&nbsp;min | β⁺ | ¹²⁶Cs | 0+ | | |-id=Barium-127 | ¹²⁷Ba | style="text-align:right" | 56 | style="text-align:right" | 71 | 126.911091(12) | 12.7(4)&nbsp;min | β⁺ | ¹²⁷Cs | 1/2+ | | |-id=Barium-127m | style="text-indent:1em" | ^127mBa | colspan="3" style="text-indent:2em" | 80.32(11)&nbsp;keV | 1.93(7)&nbsp;s | IT | ¹²⁷Ba | 7/2− | | |-id=Barium-128 | ¹²⁸Ba | style="text-align:right" | 56 | style="text-align:right" | 72 | 127.9083524(17) | 2.43(5)&nbsp;d | EC | ¹²⁸Cs | 0+ | | |-id=Barium-129 | ¹²⁹Ba | style="text-align:right" | 56 | style="text-align:right" | 73 | 128.908683(11) | 2.23(11)&nbsp;h | β⁺ | ¹²⁹Cs | 1/2+ | | |-id=Barium-129m | rowspan=2 style="text-indent:1em" | ^129mBa | rowspan=2 colspan="3" style="text-indent:2em" | 8.42(6)&nbsp;keV | rowspan=2|2.135(10)&nbsp;h | β⁺ | ¹²⁹Cs | rowspan=2|7/2+ | rowspan=2| | rowspan=2| |- | IT? | ¹²⁹Ba |-id=Barium-130 | ¹³⁰Ba | style="text-align:right" | 56 | style="text-align:right" | 74 | 129.9063260(3) | ≈&nbsp;1×10²¹&nbsp;y | εε | ¹³⁰Xe | 0+ | 0.0011(1) | |-id=Barium-130m | style="text-indent:1em" | ^130mBa | colspan="3" style="text-indent:2em" | 2475.12(18)&nbsp;keV | 9.54(14)&nbsp;ms | IT | ¹³⁰Ba | 8− | | |-id=Barium-131 | ¹³¹Ba | style="text-align:right" | 56 | style="text-align:right" | 75 | 130.9069463(4) | 11.52(1)&nbsp;d | β⁺ | ¹³¹Cs | 1/2+ | | |-id=Barium-131m | style="text-indent:1em" | ^131mBa | colspan="3" style="text-indent:2em" | 187.995(9)&nbsp;keV | 14.26(9)&nbsp;min | IT | ¹³¹Ba | 9/2− | | |-id=Barium-132 | ¹³²Ba | style="text-align:right" | 56 | style="text-align:right" | 76 | 131.9050612(11) | colspan=3 align=center|Observationally Stable | 0+ | 0.0010(1) | |-id=Barium-133 | ¹³³Ba | style="text-align:right" | 56 | style="text-align:right" | 77 |132.9060074(11) | 10.5379(16)&nbsp;y | EC | ¹³³Cs | 1/2+ | | |-id=Barium-133m | rowspan=2 style="text-indent:1em" | ^133mBa | rowspan=2 colspan="3" style="text-indent:2em" | 288.252(9)&nbsp;keV | rowspan=2|38.90(6)&nbsp;h | IT (99.99%) | ¹³³Ba | rowspan=2|11/2− | rowspan=2| | rowspan=2| |- | EC (0.0104%) | ¹³³Cs |-id=Barium-134 | ¹³⁴Ba | style="text-align:right" | 56 | style="text-align:right" | 78 | 133.90450825(27) | colspan=3 align=center|Stable | 0+ | 0.0242(15) | |-id=Barium-134m | style="text-indent:1em" | ^134mBa | colspan="3" style="text-indent:2em" | 2957.2(5)&nbsp;keV | 2.61(13)&nbsp;μs | IT | ¹³⁴Ba | 10+ | | |-id=Barium-135 | ¹³⁵Ba | style="text-align:right" | 56 | style="text-align:right" | 79 | 134.90568845(26) | colspan=3 align=center|Stable | 3/2+ | 0.0659(10) | |-id=Barium-135m1 | style="text-indent:1em" | ^135m1Ba | colspan="3" style="text-indent:2em" | 268.218(20)&nbsp;keV | 28.11(2)&nbsp;h | IT | ¹³⁵Ba | 11/2− | | |-id=Barium-135m2 | style="text-indent:1em" | ^135m2Ba | colspan="3" style="text-indent:2em" | 2388.0(5)&nbsp;keV | 1.06(4)&nbsp;ms | IT | ¹³⁵Ba | (23/2+) | | |-id=Barium-136 | ¹³⁶Ba | style="text-align:right" | 56 | style="text-align:right" | 80 |135.90457580(26) | colspan=3 align=center|Stable | 0+ | 0.0785(24) | |-id=Barium-136m1 | style="text-indent:1em" | ^136m1Ba | colspan="3" style="text-indent:2em" | 2030.535(18)&nbsp;keV | 308.4(19)&nbsp;ms | IT | ¹³⁶Ba | 7− | | |-id=Barium-136m2 | style="text-indent:1em" | ^136m2Ba | colspan="3" style="text-indent:2em" | 3357.19(25)&nbsp;keV | 91(2)&nbsp;ns | IT | ¹³⁶Ba | 10+ | | |-id=Barium-137 | ¹³⁷Ba | style="text-align:right" | 56 | style="text-align:right" | 81 |136.90582721(27) | colspan=3 align=center|Stable | 3/2+ | 0.1123(23) | |-id=Barium-137m1 | style="text-indent:1em" | ^137m1Ba | colspan="3" style="text-indent:2em" | 661.659(3)&nbsp;keV | 2.552(1)&nbsp;min | IT | ¹³⁷Ba | 11/2− | | |-id=Barium-137m2 | style="text-indent:1em" | ^137m2Ba | colspan="3" style="text-indent:2em" | 2349.1(5)&nbsp;keV | 589(20)&nbsp;ns | IT | ¹³⁷Ba | (19/2−) | | |-id=Barium-138 | ¹³⁸Ba | style="text-align:right" | 56 | style="text-align:right" | 82 | 137.90524706(27) | colspan=3 align=center|Stable | 0+ | 0.7170(29) | |-id=Barium-138m | style="text-indent:1em" | ^138mBa | colspan="3" style="text-indent:2em" | 2090.536(21)&nbsp;keV | 850(100)&nbsp;ns | IT | ¹³⁸Ba | 6+ | | |-id=Barium-139 | ¹³⁹Ba | style="text-align:right" | 56 | style="text-align:right" | 83 | 138.90884116(27) | 82.93(9)&nbsp;min | β^− | ¹³⁹La | 7/2− | | |-id=Barium-140 | ¹⁴⁰Ba | style="text-align:right" | 56 | style="text-align:right" | 84 | 139.910608(8) | 12.7534(21)&nbsp;d | β^− | ¹⁴⁰La | 0+ | | |-id=Barium-141 | ¹⁴¹Ba | style="text-align:right" | 56 | style="text-align:right" | 85 | 140.914404(6) | 18.27(7)&nbsp;min | β^− | ¹⁴¹La | 3/2− | | |-id=Barium-142 | ¹⁴²Ba | style="text-align:right" | 56 | style="text-align:right" | 86 | 141.916433(6) | 10.6(2)&nbsp;min | β^− | ¹⁴²La | 0+ | | |-id=Barium-143 | ¹⁴³Ba | style="text-align:right" | 56 | style="text-align:right" | 87 | 142.920625(7) | 14.5(3)&nbsp;s | β^− | ¹⁴³La | 5/2− | | |-id=Barium-144 | ¹⁴⁴Ba | style="text-align:right" | 56 | style="text-align:right" | 88 |143.922955(8) | 11.73(8)&nbsp;s | β^− | ¹⁴⁴La | 0+ | | |-id=Barium-145 | ¹⁴⁵Ba | style="text-align:right" | 56 | style="text-align:right" | 89 | 144.927518(9) | 4.31(16)&nbsp;s | β^− | ¹⁴⁵La | 5/2− | | |-id=Barium-146 | ¹⁴⁶Ba | style="text-align:right" | 56 | style="text-align:right" | 90 | 145.9303632(19) | 2.15(4)&nbsp;s | β^− | ¹⁴⁶La | 0+ | | |-id=Barium-147 | 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)&nbsp;ms | β^− (99.93%) | ¹⁴⁷La | rowspan=2|5/2− | rowspan=2| | rowspan=2| |- | β^−, n (0.07%) | ¹⁴⁶La |-id=Barium-148 | 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)&nbsp;ms | β^− (99.6%) | ¹⁴⁸La | rowspan=2|0+ | rowspan=2| | rowspan=2| |- | β^−, n (0.4%) | ¹⁴⁷La |-id=Barium-149 | 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)&nbsp;ms | β^− (96.1%) | ¹⁴⁹La | rowspan=2|3/2−# | rowspan=2| | rowspan=2| |- | β^−, n (3.9%) | ¹⁴⁸La |-id=Barium-150 | 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)&nbsp;ms | β^− (99.0%) | ¹⁵⁰La | rowspan=2|0+ | rowspan=2| | rowspan=2| |- | β^−, n (1.0%) | ¹⁴⁹La |-id=Barium-151 | 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)&nbsp;ms | β^− | ¹⁵¹La | rowspan=2|3/2−# | rowspan=2| | rowspan=2| |- | β^−, n? | ¹⁵⁰La |-id=Barium-152 | 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)&nbsp;ms | β^− | ¹⁵²La | rowspan=2|0+ | rowspan=2| | rowspan=2| |- | β^−, n? | ¹⁵¹La |-id=Barium-153 | 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)&nbsp;ms | β^− | ¹⁵³La | rowspan=3|5/2−# | rowspan=3| | rowspan=3| |- | β^−, n? | ¹⁵²La |- | β^−, 2n? | ¹⁵¹La |-id=Barium-154 | ¹⁵⁴Ba | style="text-align:right" | 56 | style="text-align:right" | 98 |153.96466(54)# | 53(48)&nbsp;ms | β^− | ¹⁵⁴La | 0+ | | |-id=Barium-155 | ¹⁵⁵Ba | style="text-align:right" | 56 | style="text-align:right" | 99 | | | | | | |

See also

Daughter products other than barium

• Isotopes of lanthanum
• Isotopes of caesium
• Isotopes of xenon
• Isotopes of iodine
• Isotopes of tin
• Isotopes of carbon

References