Rhenium-166

Properties and data of the isotope ¹⁶⁶Re.

Content

General data

Name of the isotope:Rhenium-166; Re-166Symbol:¹⁶⁶Re or 16675ReMass number A:166 (= number of nucleons)Atomic number Z:75 (= number of protons)Neutrons N:91Isotopic mass:165.96576(8) u (atomic weight of Rhenium-166)Nuclide mass:165.9246207 u (calculated nuclear mass without electrons)Mass excess:-31.89435 MeVMass defect:1.409624756 u (per nucleus)Nuclear binding energy:1313.05700247 MeV (per nucleus)
7.90998194 MeV (average binding energy per nucleon)Separation energy:S_N = 9.31(8) MeV (first neutron)
S_P = 0.32(8) MeV (first proton)Half-life:2.25(21) sDecay constant λ:0.3080654135822 s^-1Specific activity α:1.124371705858 × 10⁺²¹ Bq g^-1
30388424482.665 Ci g^-1Spin and parity:
(nuclear angular momentum)Year of discovery:1978

Radioactive Decay

Half-life T_½ = 2.25(21) s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	¹⁶²Ta	< 24 %	5.46(5) MeV
EE/β⁺	¹⁶⁶W	> 76 %	9.99(7) MeV

Parent Nuclides

Direct parent isotope is: ¹⁷⁰Ir.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 91) and isobaric (same nucleon number A = 166) with Rhenium-166. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 91	Isobar A = 166
52	¹⁴³Te
53	¹⁴⁴I
54	¹⁴⁵Xe
55	¹⁴⁶Cs
56	¹⁴⁷Ba
57	¹⁴⁸La
58	¹⁴⁹Ce
59	¹⁵⁰Pr
60	¹⁵¹Nd
61	¹⁵²Pm
62	¹⁵³Sm	¹⁶⁶Sm
63	¹⁵⁴Eu	¹⁶⁶Eu
64	¹⁵⁵Gd	¹⁶⁶Gd
65	¹⁵⁶Tb	¹⁶⁶Tb
66	¹⁵⁷Dy	¹⁶⁶Dy
67	¹⁵⁸Ho	¹⁶⁶Ho
68	¹⁵⁹Er	¹⁶⁶Er
69	¹⁶⁰Tm	¹⁶⁶Tm
70	¹⁶¹Yb	¹⁶⁶Yb
71	¹⁶²Lu	¹⁶⁶Lu
72	¹⁶³Hf	¹⁶⁶Hf
73	¹⁶⁴Ta	¹⁶⁶Ta
74	¹⁶⁵W	¹⁶⁶W
75	¹⁶⁶Re	¹⁶⁶Re
76	¹⁶⁷Os	¹⁶⁶Os
77	¹⁶⁸Ir	¹⁶⁶Ir
78	¹⁶⁹Pt	¹⁶⁶Pt
79	¹⁷⁰Au
80	¹⁷¹Hg