Thulium-161m

Properties and data of the isotope ^161mTm.

Contents

General data

Name of the isotope:Thulium-161m; Tm-161mSymbol:^161mTm or 161m69TmMass number A:161 (= number of nucleons)Atomic number Z:69 (= number of protons)Neutrons N:92Isotopic mass:160.93355(3) u (atomic weight of Thulium-161m)
Excitation energy: 78.20(3) keVNuclide mass:160.8957014 u (calculated nuclear mass without electrons)Mass excess:-61.89778 MeVMass defect:1.40354948 u (per nucleus)Nuclear binding energy:1307.39791932 MeV (per nucleus)
8.12048397 MeV (average binding energy per nucleon)Half-life:110(3) nsDecay constant λ:6301338.0050904 s^-1Specific activity α:2.371721567045 × 10⁺²⁸ Bq g^-1
6.410058289312 × 10⁺¹⁷ Ci g^-1Spin and parity:
(nuclear angular momentum)7/2-

Radioactive Decay

Half-life T_½ = 110(3) ns respectively 1.10 × 10^-7 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EE/β⁺	¹⁶¹Er	?
Iso	¹⁶¹Tm	?

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
¹⁶¹Tm		30.2(8) min	7/2+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 92) and isobaric (same nucleon number A = 161) with Thulium-161m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 92	Isobar A = 161
53	¹⁴⁵I
54	¹⁴⁶Xe
55	¹⁴⁷Cs
56	¹⁴⁸Ba
57	¹⁴⁹La
58	¹⁵⁰Ce
59	¹⁵¹Pr
60	¹⁵²Nd	¹⁶¹Nd
61	¹⁵³Pm	¹⁶¹Pm
62	¹⁵⁴Sm	¹⁶¹Sm
63	¹⁵⁵Eu	¹⁶¹Eu
64	¹⁵⁶Gd	¹⁶¹Gd
65	¹⁵⁷Tb	¹⁶¹Tb
66	¹⁵⁸Dy	¹⁶¹Dy
67	¹⁵⁹Ho	¹⁶¹Ho
68	¹⁶⁰Er	¹⁶¹Er
69	¹⁶¹Tm	¹⁶¹Tm
70	¹⁶²Yb	¹⁶¹Yb
71	¹⁶³Lu	¹⁶¹Lu
72	¹⁶⁴Hf	¹⁶¹Hf
73	¹⁶⁵Ta	¹⁶¹Ta
74	¹⁶⁶W	¹⁶¹W
75	¹⁶⁷Re	¹⁶¹Re
76	¹⁶⁸Os	¹⁶¹Os
77	¹⁶⁹Ir
78	¹⁷⁰Pt
79	¹⁷¹Au
80	¹⁷²Hg