Lanthanum-140

Properties and data of the isotope ¹⁴⁰La.

Content

General data

Name of the isotope:Lanthanum-140; La-140Symbol:¹⁴⁰La or 14057LaMass number A:140 (= number of nucleons)Atomic number Z:57 (= number of protons)Neutrons N:83Isotopic mass:139.9094832(22) u (atomic weight of Lanthanum-140)Nuclide mass:139.8782163 u (calculated nuclear mass without electrons)Mass excess:-84.31586 MeVMass defect:1.255731652 u (per nucleus)Nuclear binding energy:1169.70649945 MeV (per nucleus)
8.35504642 MeV (average binding energy per nucleon)Separation energy:S_N = 5.16098(4) MeV (first neutron)
S_P = 66.911(20) MeV (first proton)Half-life:1.67858(21) dDecay constant λ:4.779359227463 × 10^-6 s^-1Specific activity α:2.070645646620 × 10⁺¹⁶ Bq g^-1
559633.95854611 Ci g^-1Spin and parity:
(nuclear angular momentum)3-Magnetic dipole moment:μ(μ_N) = + 0.730(15)Quadrupole moment Q:+0.094 barn (100 fm²)Nuclear g-factor:g_l = 0.24333333333333Year of discovery:1935

Radioactive Decay

Half-life T_½ = 1.67858(21) d respectively 1.45029312 × 10⁵ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	¹⁴⁰Ce	100 %	3.7602(17) MeV

Parent Nuclides

Direct parent isotope is: ¹⁴⁰Ba.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 83) and isobaric (same nucleon number A = 140) with Lanthanum-140. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 83	Isobar A = 140
46	¹²⁹Pd
47	¹³⁰Ag
48	¹³¹Cd
49	¹³²In
50	¹³³Sn
51	¹³⁴Sb	¹⁴⁰Sb
52	¹³⁵Te	¹⁴⁰Te
53	¹³⁶I	¹⁴⁰I
54	¹³⁷Xe	¹⁴⁰Xe
55	¹³⁸Cs	¹⁴⁰Cs
56	¹³⁹Ba	¹⁴⁰Ba
57	¹⁴⁰La	¹⁴⁰La
58	¹⁴¹Ce	¹⁴⁰Ce
59	¹⁴²Pr	¹⁴⁰Pr
60	¹⁴³Nd	¹⁴⁰Nd
61	¹⁴⁴Pm	¹⁴⁰Pm
62	¹⁴⁵Sm	¹⁴⁰Sm
63	¹⁴⁶Eu	¹⁴⁰Eu
64	¹⁴⁷Gd	¹⁴⁰Gd
65	¹⁴⁸Tb	¹⁴⁰Tb
66	¹⁴⁹Dy	¹⁴⁰Dy
67	¹⁵⁰Ho	¹⁴⁰Ho
68	¹⁵¹Er
69	¹⁵²Tm
70	¹⁵³Yb
71	¹⁵⁴Lu
72	¹⁵⁵Hf
73	¹⁵⁶Ta
74	¹⁵⁷W