Samarium-166

Properties and data of the isotope ¹⁶⁶Sm.

Content

General data

Name of the isotope:Samarium-166; Sm-166Symbol:¹⁶⁶Sm or 16662SmMass number A:166 (= number of nucleons)Atomic number Z:62 (= number of protons)Neutrons N:104Isotopic mass:165.95627(43) u (atomic weight of Samarium-166)Nuclide mass:165.9222607 u (calculated nuclear mass without electrons)Mass excess:-40.73423 MeVMass defect:1.430033248 u (per nucleus)Nuclear binding energy:1332.06739031 MeV (per nucleus)
8.02450235 MeV (average binding energy per nucleon)Separation energy:S_N = 4.99(57) MeV (first neutron)Half-life:0.80(63) sDecay constant λ:0.86643397569993 s^-1Specific activity α:3.162295422727 × 10⁺²¹ Bq g^-1
85467443857.495 Ci g^-1Spin and parity:
(nuclear angular momentum)0+Year of discovery:2016

Radioactive Decay

Half-life T_½ = 0.80(63) s respectively 8.0 × 10^-1 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	¹⁶⁶Eu	100 %	6.48(54) MeV
β^-, n	¹⁶⁵Eu	?	1.92(42) MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 104) and isobaric (same nucleon number A = 166) with Samarium-166. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 104	Isobar A = 166
62	¹⁶⁶Sm	¹⁶⁶Sm
63	¹⁶⁷Eu	¹⁶⁶Eu
64	¹⁶⁸Gd	¹⁶⁶Gd
65	¹⁶⁹Tb	¹⁶⁶Tb
66	¹⁷⁰Dy	¹⁶⁶Dy
67	¹⁷¹Ho	¹⁶⁶Ho
68	¹⁷²Er	¹⁶⁶Er
69	¹⁷³Tm	¹⁶⁶Tm
70	¹⁷⁴Yb	¹⁶⁶Yb
71	¹⁷⁵Lu	¹⁶⁶Lu
72	¹⁷⁶Hf	¹⁶⁶Hf
73	¹⁷⁷Ta	¹⁶⁶Ta
74	¹⁷⁸W	¹⁶⁶W
75	¹⁷⁹Re	¹⁶⁶Re
76	¹⁸⁰Os	¹⁶⁶Os
77	¹⁸¹Ir	¹⁶⁶Ir
78	¹⁸²Pt	¹⁶⁶Pt
79	¹⁸³Au
80	¹⁸⁴Hg
81	¹⁸⁵Tl
82	¹⁸⁶Pb
83	¹⁸⁷Bi
84	¹⁸⁸Po

Literature and References

[1] - M. Thoennessen:
2017 Update of the discoveries of nuclides.
In: International Journal of Modern Physics E, (2018), DOI 10.1142/S0218301318300023.