Lanthanum-142

Properties and data of the isotope ¹⁴²La.

Content

General data

Name of the isotope:Lanthanum-142; La-142Symbol:¹⁴²La or 14257LaMass number A:142 (= number of nucleons)Atomic number Z:57 (= number of protons)Neutrons N:85Isotopic mass:141.914090(7) u (atomic weight of Lanthanum-142)Nuclide mass:141.8828231 u (calculated nuclear mass without electrons)Mass excess:-80.02465 MeVMass defect:1.268454684 u (per nucleus)Nuclear binding energy:1181.55792742 MeV (per nucleus)
8.32083047 MeV (average binding energy per nucleon)Separation energy:S_N = 5.164(7) MeV (first neutron)
S_P = 7.581(8) MeV (first proton)Half-life:91.1(5) minDecay constant λ:0.00012681068067324 s^-1Specific activity α:5.416111925948 × 10⁺¹⁷ Bq g^-1
14638140.340401 Ci g^-1Spin and parity:
(nuclear angular momentum)2-Year of discovery:1953

Radioactive Decay

Half-life T_½ = 91.1(5) min (minutes) respectively 5.466 × 10³ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	¹⁴²Ce	100 %	4.509(6) MeV

Parent Nuclides

Direct parent isotope is: ¹⁴²Ba.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 85) and isobaric (same nucleon number A = 142) with Lanthanum-142. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 85	Isobar A = 142
47	¹³²Ag
48	¹³³Cd
49	¹³⁴In
50	¹³⁵Sn
51	¹³⁶Sb
52	¹³⁷Te	¹⁴²Te
53	¹³⁸I	¹⁴²I
54	¹³⁹Xe	¹⁴²Xe
55	¹⁴⁰Cs	¹⁴²Cs
56	¹⁴¹Ba	¹⁴²Ba
57	¹⁴²La	¹⁴²La
58	¹⁴³Ce	¹⁴²Ce
59	¹⁴⁴Pr	¹⁴²Pr
60	¹⁴⁵Nd	¹⁴²Nd
61	¹⁴⁶Pm	¹⁴²Pm
62	¹⁴⁷Sm	¹⁴²Sm
63	¹⁴⁸Eu	¹⁴²Eu
64	¹⁴⁹Gd	¹⁴²Gd
65	¹⁵⁰Tb	¹⁴²Tb
66	¹⁵¹Dy	¹⁴²Dy
67	¹⁵²Ho	¹⁴²Ho
68	¹⁵³Er
69	¹⁵⁴Tm
70	¹⁵⁵Yb
71	¹⁵⁶Lu
72	¹⁵⁷Hf
73	¹⁵⁸Ta
74	¹⁵⁹W
75	¹⁶⁰Re
76	¹⁶¹Os