Samarium-148

Properties and data of the isotope ¹⁴⁸Sm.

Content

General data

Name of the isotope:Samarium-148; Sm-148Symbol:¹⁴⁸Sm or 14862SmMass number A:148 (= number of nucleons)Atomic number Z:62 (= number of protons)Neutrons N:86Isotopic mass:147.91483(2) u (atomic weight of Samarium-148)Nuclide mass:147.8808207 u (calculated nuclear mass without electrons)Mass excess:-79.33534 MeVMass defect:1.31550476 u (per nucleus)Nuclear binding energy:1225.38479091 MeV (per nucleus)
8.27962697 MeV (average binding energy per nucleon)Separation energy:S_N = 8.14123(26) MeV (first neutron)
S_P = 7.5830(4) MeV (first proton)Half-life:7(3)×10¹⁵ aDecay constant λ:3.139936129955 × 10^-24 s^-1Specific activity α:0.012863358956324 Bq g^-1
3.476583501709 × 10^-13 Ci g^-1Spin and parity:
(nuclear angular momentum)0+Charge radius:5.0042(34) femtometer fmYear of discovery:1933

Radioactive Decay

Half-life T_½ = 7(3)×10¹⁵ a respectively 2.20752 × 10²³ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	¹⁴⁴Nd	100 %	1.9868(4) MeV

Parent Nuclides

Direct parent isotopes are: ¹⁴⁸Eu, ¹⁴⁸Pm, ¹⁵²Gd.

Occurrence

Comparison of the natural Samarium isotopes including isotopic abundance (mole fraction of the isotope mixture in percent):

	Atomic Mass m_a	Quantity	Half-life	Spin
Samarium Isotopic mixture	150.36 u	100 %
Isotope ¹⁴⁴Sm	143.91201(2) u	3.08(4) %	stable	0+
Isotope ¹⁴⁸Sm	147.91483(2) u	11.25(9) %	7(3)×10¹⁵ a	0+
Isotope ¹⁴⁹Sm	148.91719(2) u	13.82(10) %	stable	7/2-
Isotope ¹⁵⁰Sm	149.91728(2) u	7.37(9) %	stable	0+
Isotope ¹⁵²Sm	151.91974(2) u	26.74(9) %	stable	0+
Isotope ¹⁵⁴Sm	153.92222(2) u	22.74(14) %	stable	0+
Isotope ¹⁴⁷Sm	146.91490(2) u	15.00(14) %	1.0625(38) × 10¹¹ a	7/2-
Isotope ¹⁴⁶Sm	145.913047(3) u	[trace]	9.20 (26) × 10⁷ a	0+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 86) and isobaric (same nucleon number A = 148) with Samarium-148. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 86	Isobar A = 148
48	¹³⁴Cd
49	¹³⁵In
50	¹³⁶Sn
51	¹³⁷Sb
52	¹³⁸Te
53	¹³⁹I
54	¹⁴⁰Xe	¹⁴⁸Xe
55	¹⁴¹Cs	¹⁴⁸Cs
56	¹⁴²Ba	¹⁴⁸Ba
57	¹⁴³La	¹⁴⁸La
58	¹⁴⁴Ce	¹⁴⁸Ce
59	¹⁴⁵Pr	¹⁴⁸Pr
60	¹⁴⁶Nd	¹⁴⁸Nd
61	¹⁴⁷Pm	¹⁴⁸Pm
62	¹⁴⁸Sm	¹⁴⁸Sm
63	¹⁴⁹Eu	¹⁴⁸Eu
64	¹⁵⁰Gd	¹⁴⁸Gd
65	¹⁵¹Tb	¹⁴⁸Tb
66	¹⁵²Dy	¹⁴⁸Dy
67	¹⁵³Ho	¹⁴⁸Ho
68	¹⁵⁴Er	¹⁴⁸Er
69	¹⁵⁵Tm	¹⁴⁸Tm
70	¹⁵⁶Yb	¹⁴⁸Yb
71	¹⁵⁷Lu
72	¹⁵⁸Hf
73	¹⁵⁹Ta
74	¹⁶⁰W
75	¹⁶¹Re
76	¹⁶²Os