Rhenium-169

Properties and data of the isotope ¹⁶⁹Re.

Contents

General data

Name of the isotope:Rhenium-169; Re-169Symbol:¹⁶⁹Re or 16975ReMass number A:169 (= number of nucleons)Atomic number Z:75 (= number of protons)Neutrons N:94Isotopic mass:168.958766(12) u (atomic weight of Rhenium-169)Nuclide mass:168.9176267 u (calculated nuclear mass without electrons)Mass excess:-38.40922 MeVMass defect:1.442613504 u (per nucleus)Nuclear binding energy:1343.78582329 MeV (per nucleus)
7.9513954 MeV (average binding energy per nucleon)Separation energy:S_N = 10.69(3) MeV (first neutron)
S_P = 0.805(16) MeV (first proton)Half-life:8.1(5) sDecay constant λ:0.085573725995055 s^-1Specific activity α:3.067482332451 × 10⁺²⁰ Bq g^-1
8290492790.4095 Ci g^-1Spin and parity:
(nuclear angular momentum)(9/2-)Year of discovery:1978

Radioactive Decay

Half-life T_½ = 8.1(5) s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	¹⁶⁵Ta	< 0.01 %	5.014(14) MeV
EC/β⁺	¹⁶⁹W	> 99.9 %	6.509(19) MeV

Parent Nuclides

Direct parent isotope is: ¹⁷³Ir.

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
^169mRe	+x keV	15.1(15) s	(5/2+,3/2+)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 94) and isobaric (same nucleon number A = 169) with Rhenium-169. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 94	Isobar A = 169
54	¹⁴⁸Xe
55	¹⁴⁹Cs
56	¹⁵⁰Ba
57	¹⁵¹La
58	¹⁵²Ce
59	¹⁵³Pr
60	¹⁵⁴Nd
61	¹⁵⁵Pm
62	¹⁵⁶Sm
63	¹⁵⁷Eu
64	¹⁵⁸Gd	¹⁶⁹Gd
65	¹⁵⁹Tb	¹⁶⁹Tb
66	¹⁶⁰Dy	¹⁶⁹Dy
67	¹⁶¹Ho	¹⁶⁹Ho
68	¹⁶²Er	¹⁶⁹Er
69	¹⁶³Tm	¹⁶⁹Tm
70	¹⁶⁴Yb	¹⁶⁹Yb
71	¹⁶⁵Lu	¹⁶⁹Lu
72	¹⁶⁶Hf	¹⁶⁹Hf
73	¹⁶⁷Ta	¹⁶⁹Ta
74	¹⁶⁸W	¹⁶⁹W
75	¹⁶⁹Re	¹⁶⁹Re
76	¹⁷⁰Os	¹⁶⁹Os
77	¹⁷¹Ir	¹⁶⁹Ir
78	¹⁷²Pt	¹⁶⁹Pt
79	¹⁷³Au
80	¹⁷⁴Hg