Samarium-151

Properties and data of the isotope ¹⁵¹Sm.

Content

General data

Name of the isotope:Samarium-151; Sm-151Symbol:¹⁵¹Sm or 15162SmMass number A:151 (= number of nucleons)Atomic number Z:62 (= number of protons)Neutrons N:89Isotopic mass:150.9199391(14) u (atomic weight of Samarium-151)Nuclide mass:150.8859298 u (calculated nuclear mass without electrons)Mass excess:-74.57625 MeVMass defect:1.336390408 u (per nucleus)Nuclear binding energy:1244.83964671 MeV (per nucleus)
8.24397117 MeV (average binding energy per nucleon)Separation energy:S_N = 5.59646(11) MeV (first neutron)
S_P = 8.268(20) MeV (first proton)Half-life:90(8) aDecay constant λ:2.442379071740 × 10^-10 s^-1Specific activity α:980556720225.51 Bq g^-1
26.501532979068 Ci g^-1Spin and parity:
(nuclear angular momentum)5/2-Magnetic dipole moment:μ(μ_N) = - 0.363Quadrupole moment Q:+0.71(7) barn (100 fm²)Nuclear g-factor:g_l = -0.1452Charge radius:5.0550(57) femtometer fmYear of discovery:1947

Radioactive Decay

Half-life T_½ = 90(8) a respectively 2.838 × 10⁹ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	¹⁵¹Eu	100 %	0.0766(5) MeV

Parent Nuclides

Direct parent isotope is: ¹⁵¹Pm.

Nuclear Isomers

Nuclear isomers or excited states with the activation energy in keV related to the ground state.

Nuclear Isomer	Excitation Energy	Half-life	Spin
^151mSm	261.13(4) keV	1.4(1) μs	(11/2)-

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 89) and isobaric (same nucleon number A = 151) with Samarium-151. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 89	Isobar A = 151
50	¹³⁹Sn
51	¹⁴⁰Sb
52	¹⁴¹Te
53	¹⁴²I
54	¹⁴³Xe
55	¹⁴⁴Cs	¹⁵¹Cs
56	¹⁴⁵Ba	¹⁵¹Ba
57	¹⁴⁶La	¹⁵¹La
58	¹⁴⁷Ce	¹⁵¹Ce
59	¹⁴⁸Pr	¹⁵¹Pr
60	¹⁴⁹Nd	¹⁵¹Nd
61	¹⁵⁰Pm	¹⁵¹Pm
62	¹⁵¹Sm	¹⁵¹Sm
63	¹⁵²Eu	¹⁵¹Eu
64	¹⁵³Gd	¹⁵¹Gd
65	¹⁵⁴Tb	¹⁵¹Tb
66	¹⁵⁵Dy	¹⁵¹Dy
67	¹⁵⁶Ho	¹⁵¹Ho
68	¹⁵⁷Er	¹⁵¹Er
69	¹⁵⁸Tm	¹⁵¹Tm
70	¹⁵⁹Yb	¹⁵¹Yb
71	¹⁶⁰Lu	¹⁵¹Lu
72	¹⁶¹Hf
73	¹⁶²Ta
74	¹⁶³W
75	¹⁶⁴Re
76	¹⁶⁵Os
77	¹⁶⁶Ir
78	¹⁶⁷Pt