Samarium-142

Properties and data of the isotope ¹⁴²Sm.

Content

General data

Name of the isotope:Samarium-142; Sm-142Symbol:¹⁴²Sm or 14262SmMass number A:142 (= number of nucleons)Atomic number Z:62 (= number of protons)Neutrons N:80Isotopic mass:141.915205(3) u (atomic weight of Samarium-142)Nuclide mass:141.8811957 u (calculated nuclear mass without electrons)Mass excess:-78.98603 MeVMass defect:1.263140264 u (per nucleus)Nuclear binding energy:1176.60757707 MeV (per nucleus)
8.28596885 MeV (average binding energy per nucleon)Separation energy:S_N = 11.124(9) MeV (first neutron)
S_P = 5.753(14) MeV (first proton)Half-life:72.49(5) minDecay constant λ:0.00015936616097851 s^-1Specific activity α:6.806563615035 × 10⁺¹⁷ Bq g^-1
18396117.878474 Ci g^-1Spin and parity:
(nuclear angular momentum)0+Charge radius:4.9518(34) femtometer fmYear of discovery:1959

Radioactive Decay

Half-life T_½ = 72.49(5) min (minutes) respectively 4.3494 × 10³ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EE/β⁺	¹⁴²Pm	100 %	2.156(24) MeV

Parent Nuclides

Direct parent isotope is: ¹⁴²Eu.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 80) and isobaric (same nucleon number A = 142) with Samarium-142. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 80	Isobar A = 142
44	¹²⁴Ru
45	¹²⁵Rh
46	¹²⁶Pd
47	¹²⁷Ag
48	¹²⁸Cd
49	¹²⁹In
50	¹³⁰Sn
51	¹³¹Sb
52	¹³²Te	¹⁴²Te
53	¹³³I	¹⁴²I
54	¹³⁴Xe	¹⁴²Xe
55	¹³⁵Cs	¹⁴²Cs
56	¹³⁶Ba	¹⁴²Ba
57	¹³⁷La	¹⁴²La
58	¹³⁸Ce	¹⁴²Ce
59	¹³⁹Pr	¹⁴²Pr
60	¹⁴⁰Nd	¹⁴²Nd
61	¹⁴¹Pm	¹⁴²Pm
62	¹⁴²Sm	¹⁴²Sm
63	¹⁴³Eu	¹⁴²Eu
64	¹⁴⁴Gd	¹⁴²Gd
65	¹⁴⁵Tb	¹⁴²Tb
66	¹⁴⁶Dy	¹⁴²Dy
67	¹⁴⁷Ho	¹⁴²Ho
68	¹⁴⁸Er
69	¹⁴⁹Tm
70	¹⁵⁰Yb
71	¹⁵¹Lu