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Isotopes of Lanthanum

List, data and properties of all known isotopes of Lanthanum.

Content
Atomic properties
Decay properties
NMR active nuclides
Radiation protection
References
Lanthanum isotopes

All atomic nuclei of the chemical element lanthanum are summarized under lanthanum isotopes; these all consist of an atomic nucleus with 57 protons and, in the uncharged state, 57 electrons. The difference between each isotope of lanthanum is based on the number of neutrons in the nucleus.

 

Naturally Occurring Lanthanum Isotopes

Two lanthanum nuclides occur in nature: lanthanum-139 and lanthanum-138, which decays radioactively with a half-life of 1011 years. The other lanthanum isotopes decay radioactively; La-137 has a half-life of about 60,000 years. The radioactive lanthanum nuclides are currently not used for technical or medical purposes.

Atomic Mass maQuantityHalf-lifeSpin
Lanthanum
Isotopic mixture		138,90547 u100 %
Isotope 138La137,907118(3) u0,08881(71) %1.02(1) × 1011 a5+
Isotope 139La138,90636(2) u99,91119(71) %stable7/2+

 

Isotope Table: Lanthanum

The two following tables list the most important data and properties of the Lanthanum isotopes. Further information on the individual Lanthanum isotopes is listed on separate pages and can be accessed via the link in column 1.

 

Atomic Properties

Isotope
Nuclide		ENAtomic Mass
[Nuclear Mass]
{Mass Excess}		Spin I
(h/2π)		Parent
123456
Lanthanum-11611657La59116 u
[115.9687331 u]
{0 MeV}
Lanthanum-11711757La60116.95011(21) u
[116.9188431 u]
{-46.47224 MeV}		(3/2)+-
Lanthanum-117m117m57La60116.95011(21) u
[116.9188431 u]
{-46.47224 MeV}		(9/2+)
Lanthanum-11811857La61117.94673(32) u
[117.9154631 u]
{-49.62069 MeV}
Lanthanum-11911957La62118.94099(43) u
[118.9097231 u]
{-54.96746 MeV}		11/2-~119Ce
Lanthanum-12012057La63119.93820(32) u
[119.9069331 u]
{-57.56633 MeV}		120Ce
Lanthanum-12112157La64120.93324(32) u
[120.9019731 u]
{-62.18654 MeV}		(11/2-)121Ce
Lanthanum-12212257La65121.93071(32) u
[121.8994431 u]
{-64.54322 MeV}		122Ce
Lanthanum-12312357La66122.92630(21) u
[122.8950331 u]
{-68.65111 MeV}		(11/2-)123Ce
Lanthanum-12412457La67123.92457(6) u
[123.8933031 u]
{-70.26259 MeV}		8-124Ce
Lanthanum-124m124m57La67123.92457(6) u
[123.8933031 u]
{-70.26259 MeV}		(8-)
Lanthanum-12512557La68124.920816(28) u
[124.8895491 u]
{-73.75942 MeV}		(3/2+)125Ce
Lanthanum-125m125m57La68124.920816(28) u
[124.8895491 u]
{-73.75942 MeV}
Lanthanum-12612657La69125.91951(10) u
[125.8882431 u]
{-74.97595 MeV}		(5+)126Ce
Lanthanum-126m126m57La69125.91951(10) u
[125.8882431 u]
{-74.97595 MeV}
Lanthanum-12712757La70126.916375(28) u
[126.8851081 u]
{-77.89619 MeV}		(11/2-)127Ce
Lanthanum-127m127m57La70126.916375(28) u
[126.8851081 u]
{-77.89619 MeV}		(3/2+)
Lanthanum-12812857La71127.91559(6) u
[127.8843231 u]
{-78.62741 MeV}		(5+)128Ce
Lanthanum-128m128m57La71127.91559(6) u
[127.8843231 u]
{-78.62741 MeV}		(1+,2-)
Lanthanum-12912957La72128.912694(23) u
[128.8814271 u]
{-81.32502 MeV}		(3/2+)129Ce
Lanthanum-129m129m57La72128.912694(23) u
[128.8814271 u]
{-81.32502 MeV}		(11/2-)
Lanthanum-13013057La73129.912369(28) u
[129.8811021 u]
{-81.62775 MeV}		3(+)130Ce
Lanthanum-13113157La74130.91007(3) u
[130.8788031 u]
{-83.76926 MeV}		3/2+131Ce
Lanthanum-131m131m57La74130.91007(3) u
[130.8788031 u]
{-83.76926 MeV}		11/2-
Lanthanum-13213257La75131.91012(4) u
[131.8788531 u]
{-83.72268 MeV}		2-132Ce
Lanthanum-132m132m57La75131.91012(4) u
[131.8788531 u]
{-83.72268 MeV}		6-
Lanthanum-13313357La76132.90822(3) u
[132.8769531 u]
{-85.49252 MeV}		5/2+133Ce
Lanthanum-13413457La77133.908514(21) u
[133.8772471 u]
{-85.21866 MeV}		1+134Ce
Lanthanum-13513557La78134.906985(10) u
[134.8757181 u]
{-86.64291 MeV}		5/2+135Ce
Lanthanum-13613657La79135.90763(6) u
[135.8763631 u]
{-86.0421 MeV}		1+
Lanthanum-136m136m57La79135.90763(6) u
[135.8763631 u]
{-86.0421 MeV}		(7-)
Lanthanum-13713757La80136.9064506(18) u
[136.8751837 u]
{-87.1407 MeV}		7/2+137Ce
Lanthanum-13813857La81137.907118(3) u
[137.8758511 u]
{-86.51903 MeV}		5+
Lanthanum-138m138m57La81137.907118(3) u
[137.8758511 u]
{-86.51903 MeV}		(3)+
Lanthanum-13913957La82138.90636(2) u
[138.8750931 u]
{-87.2251 MeV}		7/2+139Ce
139Ba
Lanthanum-14014057La83139.9094832(22) u
[139.8782163 u]
{-84.31586 MeV}		3-140Ba
Lanthanum-14114157La84140.910969(5) u
[140.8797021 u]
{-82.93184 MeV}		(7/2+)141Ba
Lanthanum-14214257La85141.914090(7) u
[141.8828231 u]
{-80.02465 MeV}		2-142Ba
Lanthanum-14314357La86142.916079(8) u
[142.8848121 u]
{-78.17191 MeV}		(7/2)+143Ba
Lanthanum-14414457La87143.919646(14) u
[143.8883791 u]
{-74.84927 MeV}		(3-)144Ba
Lanthanum-14514557La88144.921808(13) u
[144.8905411 u]
{-72.83538 MeV}		(5/2+)145Ba
Lanthanum-14614657La89145.92587(4) u
[145.8946031 u]
{-69.05165 MeV}		2-146Ba
Lanthanum-146m146m57La89145.92587(4) u
[145.8946031 u]
{-69.05165 MeV}		(6-)
Lanthanum-14714757La90146.928418(11) u
[146.8971511 u]
{-66.6782 MeV}		(3/2+)147Ba
Lanthanum-14814857La91147.932679(21) u
[147.9014121 u]
{-62.70911 MeV}		(2-)148Ba
Lanthanum-14914957La92148.93535(21) u
[148.9040831 u]
{-60.22109 MeV}		(3/2-)149Ba
Lanthanum-15015057La93149.93974(47) u
[149.9084731 u]
{-56.13183 MeV}		(3+)150Ba
Lanthanum-15115157La94150.94277(47) u
[150.9115031 u]
{-53.3094 MeV}		(1/2+)151Ba
Lanthanum-15215257La95151.94708(32) u
[151.9158131 u]
{-49.29466 MeV}		(2-)152Ba
Lanthanum-15315357La96152.95055(32) u
[152.9192831 u]
{-46.06238 MeV}		(1/2+)153Ba
Lanthanum-15415457La97153.95542(32) u
[153.9241531 u]
{-41.526 MeV}		(2-)
Lanthanum-15515557La98154.95928(43) u
[154.9280131 u]
{-37.93044 MeV}		(1/2+)
Lanthanum-15615657La99155.96452(43) u
[155.9332531 u]
{-33.04941 MeV}		(4+)

 

Radioactive Decay Properties

IsotopeRadioactive DecayExtern
Half-lifeDecay ModeProbabilityEnergy
789101112
La-11650(22) msp → 115Ba
βsup>+ → 116Ba		60 %
40 %
AL
La-11723.5(25) msp → 116Ba
β+ → 117Ba		93.9(7) %
6.1(7) %
10.99(32) MeV		AL
La-117m10(5) msp → 116Ba
β+ → 117Ba		97.4(13) %
2.6(13) %
AL
La-118~200 msβ+ → 118Ba
β+ →

AL
La-119~1 sβ+ → 119BaAL
La-1202.8(2) sEC/β+ → 120Ba
EC, p → 119Cs		< 100 %
> 0 %		11.32(42) MeV
AL
La-1215.3(2) sβ+ → 121Ba100 %8.55(33) MeVAL
La-1228.6(5) sEC/β+ → 122Ba
EC, p → 121Cs		100 %
?		10.07(30) MeV
AL
La-12317(3) sEC/β+ → 123Ba100 %7.00(20) MeVAL
La-12421(4) sEC/β+ → 124Ba100 %8.83(6) MeVAL
La-124m29.21(17) sEC/β+ → 124Ba100 %AL
La-12564.8(12) sEC/β+ → 125Ba100 %5.909(28) MeVAL
La-125m0.39(4) sAL
La-12654(2) sEC/β+ → 126Ba?7.79(9) MeVAL
La-126m50 sEC/β+ → 126Ba
Iso → 126La		?
?
AL
La-1275.1(1) minEC/β+ → 127Ba100 %4.922(28) MeVAL
La-127m3.7(4) minEC/β+ → 127Ba100 %AL
La-1285.18(14) minEC/β+ → 128Ba100 %6.75(5) MeVAL
La-128m1.4 minEC → 128Ba100 %AL
La-12911.6(2) minβ+ → 129Ba100 %3.739(24) MeVAL
La-129m0.56(5) sIso → 129La100 %AL
La-1308.7(1) minEC/β+ → 130Ba5.634(26) MeVAL
La-13159(2) minEC/β+ → 131Ba100 %2.914(28) MeVAL
La-131m170(7) μsIso → 131La100 %AL
La-1324.8(2) hEC/β+ → 132Ba100 %4.71(4) MeVAL
La-132m24.3(5) minIso → 132La
EC/β+ → 132Ba		76 %
24 %
AL
La-1333.912(8) hEC/β+ → 133Ba100 %2.059(28) MeVAL
La-1346.45(16) minEC/β+ → 134Ba100 %3.731(20) MeVAL
La-13519.5(2) hEC/β+ → 135Ba100 %1.207(9) MeVAL
La-1369.87(3) minEC/β+ → 136Ba100 %2.85(5) MeVAL
La-136m114(5) msIso → 136La100 %AL
La-13760000 aEC → 137Ba100 %0.5805(17) MeVAL
La-1381.02(1) × 1011 aβ+ → 138Ba
β- → 138Ce		65.6(5) %
34.4(5) %		1.742(3) MeV
1.052(4) MeV		AL
La-138m116(5) nsAL
La-139stableAL
La-1401.67858(21) dβ- → 140Ce100 %3.7602(17) MeVAL
La-1413.92(3) hβ- → 141Ce100 %2.501(4) MeVAL
La-14291.1(5) minβ- → 142Ce100 %4.509(6) MeVAL
La-14314.2(1) minβ- → 143Ce100 %3.435(8) MeVAL
La-14440.8(4) sβ- → 144Ce100 %5.582(13) MeVAL
La-14524.8(20) sβ- → 145Ce100 %4.23(4) MeVAL
La-1466.1(3) sβ- → 146Ce
β-, n → 145Ce		99.99 %
0.007 %		6.59(3) MeV
AL
La-146m9.8(4) sβ- → 146Ce
Iso → 146La		100 %
?		6.7 MeV
AL
La-1474.06(4) sβ- → 147Ce
β-, n → 146Ce		99.96 %
0.041(4) %		5.336(14) MeV
0.886(20) MeV		AL
La-1481.26(8) sβ- → 148Ce
β-, n → 147Ce		99.85 %
0.15(3) %		7.690(22) MeV
1.234(21) MeV		AL
La-1491.05(3) sβ- → 149Ce
β-, n → 148Ce		98.6 %
1.43(28) %		6.45(20) MeV
2.11(20) MeV		AL
La-1500.59(11) sβ- → 150Ce
β-, n → 149Ce		97.3 %
2.7(3) %		8.72(44) MeV
2.47(44) MeV		AL
La-151457 msβ- → 151Ce
β-, n → 150Ce		100 %
?		7.91(44) MeV
3.47(44) MeV		AL
La-152298 msβ- → 152Ce
β-, n → 151Ce		100 %
?		9.69(36) MeV
3.86(20) MeV		AL
La-153245(18) msβ- → 153Ce
β-, n → 152Ce		100 %
?		8.85(36) MeV
4.85(36) MeV		AL
La-154161(15) msβ- → 154Ce
β-, n → 153Ce		100 %
?		10.69(36) MeV
5.31(36) MeV		AL
La-155101(28) msβ- → 155Ce
β-, n → 154Ce		100 %
?		9.85(50) MeV
6.22(45) MeV		AL
La-15684(78) msβ- → 156Ce
β-, n → 155Ce		100 %
?		11.77(50) MeV
6.66(50) MeV

 

Notes (related to the columns):

1 - name of the nuclide, isotope.
2 - E: isotope symbol with mass number (superscript; number of nucleons) and Atomic number (subscript; number of protons).
3 - N: number of neutrons.
4 - relative atomic mass of the Lanthanum isotope (isotopic mass including electrons) and the mass of the atomic nucleus in square brackets (nuclear mass, nuclide mass without electrons), each related to 12C = 12.00000 [2]. In addition, the mass excess is given in MeV.
5 - nuclear spin I, unit: h/2π.
6 - source nuclides: Possible, assumed or actual source nuclides (mother nuclides, parent nuclides). If applicable, the corresponding decay modes can be found in the data for the respective starting nuclide.

7 - isotope notation in short form.
8 - decay: half-live of the Lanthanum isotope (a = years; ; d = days; h = hours; min = minutes; s = seconds).
9 - decay mode: type of decay into the respective daughter nuclides with n = neutron emission; p = proton emission; α = alpha decay; β- = beta minus decay with electron emission; EC = electron capture; β+ = positron emission; ε = β+ and/or EC; Iso = isomeric transition; CD = cluster decay; SF = spontaneous decay.
10 - decay probability in percent (%).
11 - decay energy; Particle energy related to decay type.
12 - other information and notes: AL = Adopted Levels (link to external data [1]).

Miscellaneous:

()- Numbers in brackets: uncertainty to represent the spread of the reported value.
~ - Theoretical values or systematic trends.
  - unlisted-: Nuclides that have already been mentioned in the literature but for some reason can no longer be found in the current nuclide tables because their discovery e.g. has not confirmed.

 

NMR active Lanthanum nuclides

Nuclide
quantity 1)
spin		Nuclear
magnetic
moment
μ/μN		Gyromagnetic ratio
{Quadrupole moment}		Resonant
frequency
v0 bei 1 T		Relative
sensitivity
H0 = const.
v0 = const. 3)
138La
0,08881(71) %
5+		+3,7084(2)3,5575
{+ 0,45(2)}		5,66150,09404
5,3189
139La
99,91119(71) %
7/2+		+2,7791(2)3,801
{+ 0,206(4)}		6,06120,06058
2,9895

1) Quantity Percentage of natural occurrence.

2) Gyromagnetic ratio: 107 rad T-1 s-1
    Quadrupole moment: Q [barn] = [100 fm2]

3) Related to 1H = 1,000.

 

Radiation Protection

According to the Radiation Protection Ordinance (StrlSchV 2018, Germany), the following values (columns 1 to 7) apply to the handling of Lanthanum radionuclides:

NuclideLimit ValueHASS limitSCDaughter NuclidesHalf-life
La-131106 Bq10 Bq/g59.0 min
La-132106 Bq10 Bq/g4.8 h
La-135107 Bq1000 Bq/g19.5 h
La-137107 Bq100 Bq/g6.0 × 104 a
La-138107 Bq0,1 Bq/g1.0 × 1011 a
La-140105 Bq1 Bq/g0,03 TBq1 Bq cm-240.3 h
La-141105 Bq100 Bq/g3.9 h
La-142105 Bq10 Bq/g91.1 min
La-143105 Bq100 Bq/g14.1 min

(HASS = High-Activity Sealed Radioactive Sources; SC = surface contamination)

 

Literature Sources and References

Properties of the Lanthanum nucleides

[1] - NuDat: National Nuclear Data Center, Brookhaven National Laboratory, based on ENSDF and the Nuclear Wallet Cards.

[2] - G. Audi et. al.: The NUBASE evaluation of nuclear and decay properties. Nuclear Physics, (2003), DOI 10.1016/j.nuclphysa.2003.11.001.

[3] - Live Chart of Nuclides. Nuclear structure and decay data.

Lanthanum: NMR properties - 138La-NMR, 139La-NMR

[4] - N. J. Stone: Table of nuclear magnetic dipole and electric quadrupole moments. Atomic Data and Nuclear Data Tables, (2005), DOI 10.1016/j.adt.2005.04.001.

[5] - Pekka Pyykkö: Year-2008 nuclear quadrupole moments. Molecular Physics, (2008), DOI 10.1080/00268970802018367.

[6] - Pekka Pyykkö: Year-2017 nuclear quadrupole moments. Molecular Physics, (2018), DOI 10.1080/00268976.2018.1426131.

[7] - N. J. Stone: Table of recommended nuclear magnetic dipole moments. IAEA, (2019).

More sources:

[8] - Isotopic abundances, atomic weights and isotopic masses: see respective keyword.

 

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