Isotopes of lanthanum

Naturally occurring lanthanum (₅₇La) is composed of one stable (¹³⁹La) and one radioactive (¹³⁸La) isotope, with the stable isotope, ¹³⁹La, being the most abundant (99.911% natural abundance). There are 39 radioisotopes that have been characterized, with the most stable being ¹³⁸La, with a half-life of 1.03×10¹¹ years; ¹³⁷La, with a half-life of 60,000 years and ¹⁴⁰La, with a half-life of 40.289 hours. The remaining radioactive isotopes have half-lives that are less than a day and the majority of these less than a minute. This element also has 12 nuclear isomers, the longest-lived of which is ^132mLa, with a half-life of 24.3 minutes. Lighter isotopes mostly decay to isotopes of barium and heavy ones mostly decay to isotopes of cerium. ¹³⁸La can decay to both.

The known isotopes of lanthanum range from ¹¹⁶La to ¹⁵⁵La.

List of isotopes

|-id=Lanthanum-116 | rowspan=2|¹¹⁶La | rowspan=2 style="text-align:right" | 57 | rowspan=2 style="text-align:right" | 59 | rowspan=2|115.95701(35)# | rowspan=2|50(22)&nbsp;ms | p (~60%) | ¹¹⁵Ba | rowspan=2| | rowspan=2| | rowspan=2| |- | β⁺ (~40%) | ¹¹⁶Ba |-id=Lanthanum-116m | style="text-indent:1em" | ^116mLa | colspan="3" style="text-indent:2em" | 182&nbsp;keV | | IT | ¹¹⁶La | | | |-id=Lanthanum-117 | rowspan=2|¹¹⁷La | rowspan=2 style="text-align:right" | 57 | rowspan=2 style="text-align:right" | 60 | rowspan=2|116.95033(22)# | rowspan=2|21.6(31)&nbsp;ms | p (94%) | ¹¹⁶Ba | rowspan=2|(3/2+) | rowspan=2| | rowspan=2| |- | β⁺ (6%) | ¹¹⁷Ba |-id=Lanthanum-117m | style="text-indent:1em" | ^117mLa | colspan="3" style="text-indent:2em" | 192&nbsp;keV | | IT | ¹¹⁷La | (7/2−) | | |-id=Lanthanum-118 | ¹¹⁸La | style="text-align:right" | 57 | style="text-align:right" | 61 | 117.94673(32)# | 200#&nbsp;ms [>310&nbsp;ns] | | | 1−# | | |-id=Lanthanum-119 | ¹¹⁹La | style="text-align:right" | 57 | style="text-align:right" | 62 | 118.94093(32)# | 1#&nbsp;s [>310&nbsp;ns] | | | 11/2−# | | |-id=Lanthanum-120 | rowspan=2|¹²⁰La | rowspan=2 style="text-align:right" | 57 | rowspan=2 style="text-align:right" | 63 | rowspan=2|119.93820(32)# | rowspan=2|2.8(2)&nbsp;s | β⁺ | ¹²⁰Ba | rowspan=2|4+ | rowspan=2| | rowspan=2| |- | β⁺, p (?%) | ¹¹⁹Cs |-id=Lanthanum-121 | ¹²¹La | style="text-align:right" | 57 | style="text-align:right" | 64 | 120.93324(32)# | 5.3(2)&nbsp;s | β⁺ | ¹²¹Ba | 11/2−# | | |-id=Lanthanum-122 | rowspan=2|¹²²La | rowspan=2 style="text-align:right" | 57 | rowspan=2 style="text-align:right" | 65 | rowspan=2|121.93071(32)# | rowspan=2|8.6(5)&nbsp;s | β⁺ | ¹²²Ba | rowspan=2|2+ | rowspan=2| | rowspan=2| |- | β⁺, p (?%) | ¹²¹Cs |-id=Lanthanum-123 | ¹²³La | style="text-align:right" | 57 | style="text-align:right" | 66 | 122.92630(21)# | 17(3)&nbsp;s | β⁺ | ¹²³Ba | 11/2−# | | |-id=Lanthanum-124 | ¹²⁴La | style="text-align:right" | 57 | style="text-align:right" | 67 | 123.924574(61) | 29.21(17)&nbsp;s | β⁺ | ¹²⁴Ba | (7−, 8−) | | |-id=Lanthanum-124m | style="text-indent:1em" | ^124mLa | colspan="3" style="text-indent:2em" | 100(100)#&nbsp;keV | 21(4)&nbsp;s | β⁺ | ¹²⁴Ba | 2−# | | |-id=Lanthanum-125 | ¹²⁵La | style="text-align:right" | 57 | style="text-align:right" | 68 | 124.920816(28) | 64.8(12)&nbsp;s | β⁺ | ¹²⁵Ba | 11/2−# | | |-id=Lanthanum-125m | style="text-indent:1em" | ^125mLa | colspan="3" style="text-indent:2em" | 107.00(10)&nbsp;keV | 390(40)&nbsp;ms | IT | ¹²⁵La | (3/2+) | | |-id=Lanthanum-126 | ¹²⁶La | style="text-align:right" | 57 | style="text-align:right" | 69 | 125.919513(97) | 54(2)&nbsp;s | β⁺ | ¹²⁶Ba | 5−# | | |-id=Lanthanum-126m | style="text-indent:1em" | ^126mLa | colspan="3" style="text-indent:2em" | 210(410)&nbsp;keV | 20(20)&nbsp;s | β⁺ | ¹²⁶Ba | 1−# | | |-id=Lanthanum-127 | ¹²⁷La | style="text-align:right" | 57 | style="text-align:right" | 70 | 126.916375(28) | 5.1(1)&nbsp;min | β⁺ | ¹²⁷Ba | (11/2−) | | |-id=Lanthanum-127m | style="text-indent:1em" | ^127mLa | colspan="3" style="text-indent:2em" | 14.2(4)&nbsp;keV | 3.7(4)&nbsp;min | β⁺ | ¹²⁷Ba | (3/2+) | | |-id=Lanthanum-128 | ¹²⁸La | style="text-align:right" | 57 | style="text-align:right" | 71 | 127.915592(58) | 5.18(14)&nbsp;min | β⁺ | ¹²⁸Ba | (5+) | | |-id=Lanthanum-128m | style="text-indent:1em" | ^128mLa | colspan="3" style="text-indent:2em" | 100(100)#&nbsp;keV | <&nbsp;1.4&nbsp;min | β⁺ | ¹²⁸Ba | (1+, 2−) | | |-id=Lanthanum-129 | ¹²⁹La | style="text-align:right" | 57 | style="text-align:right" | 72 | 128.912696(23) | 11.6(2)&nbsp;min | β⁺ | ¹²⁹Ba | (3/2+) | | |-id=Lanthanum-129m | style="text-indent:1em" | ^129mLa | colspan="3" style="text-indent:2em" | 172.33(20)&nbsp;keV | 560(50)&nbsp;ms | IT | ¹²⁹La | (11/2−) | | |-id=Lanthanum-130 | ¹³⁰La | style="text-align:right" | 57 | style="text-align:right" | 73 | 129.912369(28) | 8.7(1)&nbsp;min | β⁺ | ¹³⁰Ba | 3(+) | | |-id=Lanthanum-130m | style="text-indent:1em" | ^130mLa | colspan="3" style="text-indent:2em" | 214.0(5)&nbsp;keV | 742(28)&nbsp;ns | IT | ¹³⁰La | (5+) | | |-id=Lanthanum-131 | ¹³¹La | style="text-align:right" | 57 | style="text-align:right" | 74 | 130.910070(30) | 59(2)&nbsp;min | β⁺ | ¹³¹Ba | 3/2+ | | |-id=Lanthanum-131m | style="text-indent:1em" | ^131mLa | colspan="3" style="text-indent:2em" | 304.52(24)&nbsp;keV | 170(10)&nbsp;μs | IT | ¹³¹La | 11/2− | | |-id=Lanthanum-132 | ¹³²La | style="text-align:right" | 57 | style="text-align:right" | 75 | 131.910119(39) | 4.59(4)&nbsp;h | β⁺ | ¹³²Ba | 2− | | |-id=Lanthanum-132m | rowspan=2 style="text-indent:1em" | ^132mLa | rowspan=2 colspan="3" style="text-indent:2em" | 188.20(11)&nbsp;keV | rowspan=2|24.3(5)&nbsp;min | IT (76%) | ¹³²La | rowspan=2|6− | rowspan=2| | rowspan=2| |- | β⁺ (24%) | ¹³²Ba |-id=Lanthanum-133 | ¹³³La | style="text-align:right" | 57 | style="text-align:right" | 76 | 132.908218(30) | 3.912(8)&nbsp;h | β⁺ | ¹³³Ba | 5/2+ | | |-id=Lanthanum-134 | ¹³⁴La | style="text-align:right" | 57 | style="text-align:right" | 77 | 133.908514(21) | 6.45(16)&nbsp;min | β⁺ | ¹³⁴Ba | 1+ | | |-id=Lanthanum-134m | style="text-indent:1em" | ^134mLa | colspan="3" style="text-indent:2em" | 440(100)#&nbsp;keV | 29(4)&nbsp;μs | IT | ¹³⁴La | (6−) | | |-id=Lanthanum-135 | ¹³⁵La | style="text-align:right" | 57 | style="text-align:right" | 78 | 134.906984(10) | 18.91(2)&nbsp;h | β⁺ | ¹³⁵Ba | 5/2+ | | |-id=Lanthanum-136 | ¹³⁶La | style="text-align:right" | 57 | style="text-align:right" | 79 | 135.907635(57) | 9.87(3)&nbsp;min | β⁺ | ¹³⁶Ba | 1+ | | |-id=Lanthanum-136m1 | style="text-indent:1em" | ^136m1La | colspan="3" style="text-indent:2em" | 259.5(3)&nbsp;keV | 114(5)&nbsp;ms | IT | ¹³⁶La | (7−) | | |-id=Lanthanum-136m2 | style="text-indent:1em" | ^136m2La | colspan="3" style="text-indent:2em" | 2520.6(4)&nbsp;keV | 187(27)&nbsp;ns | IT | ¹³⁶La | (14+) | | |-id=Lanthanum-137 | ¹³⁷La | style="text-align:right" | 57 | style="text-align:right" | 80 | 136.9064504(18) | 6(2)×10⁴&nbsp;y | EC | ¹³⁷Ba | 7/2+ | | |-id=Lanthanum-137m | style="text-indent:1em" | ^137mLa | colspan="3" style="text-indent:2em" | 1869.50(21)&nbsp;keV | 342(25)&nbsp;ns | IT | ¹³⁷La | 19/2− | | |-id=Lanthanum-138 | rowspan=2|¹³⁸La | rowspan=2 style="text-align:right" | 57 | rowspan=2 style="text-align:right" | 81 | rowspan=2|137.90712404(45) | rowspan=2|1.03(1)×10¹¹&nbsp;y | β⁺ (65.5%) | ¹³⁸Ba | rowspan=2|5+ | rowspan=2|8.881(71)×10^{−4} | rowspan=2| |- | β^− (34.5%) | ¹³⁸Ce |-id=Lanthanum-138m1 | style="text-indent:1em" | ^138m1La | colspan="3" style="text-indent:2em" | 72.57(3)&nbsp;keV | 116(5)&nbsp;ns | IT | ¹³⁸La | (3)+ | | |-id=Lanthanum-138m2 | style="text-indent:1em" | ^138m2La | colspan="3" style="text-indent:2em" | 738.80(20)&nbsp;keV | 2.0(3)&nbsp;μs | IT | ¹³⁸La | 7− | | |-id=Lanthanum-139 | ¹³⁹La | style="text-align:right" | 57 | style="text-align:right" | 82 | 138.90636293(65) | colspan=3 align=center|Stable | 7/2+ | 0.9991119(71) | |-id=Lanthanum-139m | style="text-indent:1em" | ^139mLa | colspan="3" style="text-indent:2em" | 1800.4(4)&nbsp;keV | 315(35)&nbsp;ns | IT | ¹³⁹La | (17/2+) | | |-id=Lanthanum-140 | ¹⁴⁰La | style="text-align:right" | 57 | style="text-align:right" | 83 | 139.90948729(65) | 40.289(4)&nbsp;h | β^− | ¹⁴⁰Ce | 3− | | |-id=Lanthanum-141 | ¹⁴¹La | style="text-align:right" | 57 | style="text-align:right" | 84 | 140.9109712(44) | 3.92(3)&nbsp;h | β^− | ¹⁴¹Ce | (7/2+) | | |-id=Lanthanum-142 | ¹⁴²La | style="text-align:right" | 57 | style="text-align:right" | 85 | 141.9140908(67) | 91.1(5)&nbsp;min | β^− | ¹⁴²Ce | 2− | | |-id=Lanthanum-142m | style="text-indent:1em" | ^142mLa | colspan="3" style="text-indent:2em" | 145.82(8)&nbsp;keV | 0.87(17)&nbsp;μs | IT | ¹⁴²La | (4)− | | |-id=Lanthanum-143 | ¹⁴³La | style="text-align:right" | 57 | style="text-align:right" | 86 | 142.9160795(79) | 14.2(1)&nbsp;min | β^− | ¹⁴³Ce | (7/2)+ | | |-id=Lanthanum-144 | ¹⁴⁴La | style="text-align:right" | 57 | style="text-align:right" | 87 | 143.919646(14) | 44.0(7)&nbsp;s | β^− | ¹⁴⁴Ce | (3−) | | |-id=Lanthanum-145 | ¹⁴⁵La | style="text-align:right" | 57 | style="text-align:right" | 88 | 144.921808(13) | 24.8(20)&nbsp;s | β^− | ¹⁴⁵Ce | (5/2+) | | |-id=Lanthanum-146 | ¹⁴⁶La | style="text-align:right" | 57 | style="text-align:right" | 89 | 145.9256880(18) | 9.9(1)&nbsp;s | β^− | ¹⁴⁶Ce | (5−) | | |-id=Lanthanum-146m | style="text-indent:1em" | ^146mLa | colspan="3" style="text-indent:2em" | 141.5(24)&nbsp;keV | 6.08(22)&nbsp;s | β^− | ¹⁴⁶Ce | (1−, 2−) | | |-id=Lanthanum-147 | rowspan=2|¹⁴⁷La | rowspan=2 style="text-align:right" | 57 | rowspan=2 style="text-align:right" | 90 | rowspan=2|146.928418(12) | rowspan=2|4.026(20)&nbsp;s | β^− (99.96%) | ¹⁴⁷Ce | rowspan=2|(5/2+) | rowspan=2| | rowspan=2| |- | β^−, n (0.041%) | ¹⁴⁶Ce |-id=Lanthanum-148 | rowspan=2|¹⁴⁸La | rowspan=2 style="text-align:right" | 57 | rowspan=2 style="text-align:right" | 91 | rowspan=2|147.932679(21) | rowspan=2|1.414(25)&nbsp;s | β^− (99.82%) | ¹⁴⁸Ce | rowspan=2|(2−) | rowspan=2| | rowspan=2| |- | β^−, n (0.18%) | ¹⁴⁷Ce |-id=Lanthanum-149 | rowspan=2|¹⁴⁹La | rowspan=2 style="text-align:right" | 57 | rowspan=2 style="text-align:right" | 92 | rowspan=2|148.93535(21) | rowspan=2|1.071(22)&nbsp;s | β^− (98.57%) | ¹⁴⁹Ce | rowspan=2|(3/2−) | rowspan=2| | rowspan=2| |- | β^−, n (1.43%) | ¹⁴⁸Ce |-id=Lanthanum-150 | rowspan=2|¹⁵⁰La | rowspan=2 style="text-align:right" | 57 | rowspan=2 style="text-align:right" | 93 | rowspan=2|149.9395475(27) | rowspan=2|504(15)&nbsp;ms | β^− (97.3%) | ¹⁵⁰Ce | rowspan=2|(3+) | rowspan=2| | rowspan=2| |- | β^−, n (2.7%) | ¹⁴⁹Ce |-id=Lanthanum-151 | ¹⁵¹La | style="text-align:right" | 57 | style="text-align:right" | 94 | 150.94277(47) | 465(24)&nbsp;ms | β^− | ¹⁵¹Ce | 1/2+# | | |-id=Lanthanum-152 | ¹⁵²La | style="text-align:right" | 57 | style="text-align:right" | 95 | 151.94709(32)# | 287(16)&nbsp;ms | β^− | ¹⁵²Ce | 2−# | | |-id=Lanthanum-153 | ¹⁵³La | style="text-align:right" | 57 | style="text-align:right" | 96 | 152.95055(32)# | 245(18)&nbsp;ms | β^− | ¹⁵³Ce | 1/2+# | | |-id=Lanthanum-154 | ¹⁵⁴La | style="text-align:right" | 57 | style="text-align:right" | 97 | 153.95542(32)# | 161(15)&nbsp;ms | β^− | ¹⁵⁴Ce | 2−# | | |-id=Lanthanum-155 | ¹⁵⁵La | style="text-align:right" | 57 | style="text-align:right" | 98 | 154.95928(43)# | 101(28)&nbsp;ms | β^− | ¹⁵⁵Ce | 1/2+# | | |-id=Lanthanum-156 | ¹⁵⁶La | style="text-align:right" | 57 | style="text-align:right" | 99 | 155.96452(43)# | 84(78)&nbsp;ms | β^− | ¹⁵⁶Ce | 4+# | | |-id=Lanthanum-157 | ¹⁵⁷La | style="text-align:right" | 57 | style="text-align:right" | 100 | 156.96879(32)# | 30#&nbsp;ms[>&nbsp;550&nbsp;ns] | | | 1/2+# | | |-id=Lanthanum-158 | ¹⁵⁸La | style="text-align:right" | 57 | style="text-align:right" | 101 | | | | | | |

See also

Daughter products other than lanthanum

• Isotopes of cerium
• Isotopes of barium
• Isotopes of caesium

References

• Isotope masses from:
• Isotopic compositions and standard atomic masses from:
• Half-life, spin, and isomer data selected from the following sources.