Thallium-188m1

Properties and data of the isotope ¹⁸⁸Tl.

Content

General data

Name of the isotope:Thallium-188m1; Tl-188m1Symbol:¹⁸⁸Tl or 18881TlMass number A:188 (= number of nucleons)Atomic number Z:81 (= number of protons)Neutrons N:107Isotopic mass:187.97602(3) u (atomic weight of Thallium-188m1)
Excitation energy: 35(31) keVNuclide mass:187.93159 u (calculated nuclear mass without electrons)Mass excess:-22.33723 MeVMass defect:1.584953604 u (per nucleus)Nuclear binding energy:1476.3747724 MeV (per nucleus)
7.8530573 MeV (average binding energy per nucleon)Half-life:71.5(15) sDecay constant λ:0.0096943661616776 s^-1Specific activity α:3.121969977188 × 10⁺¹⁹ Bq g^-1
843775669.51043 Ci g^-1Spin and parity:
(nuclear angular momentum)(7+)Magnetic dipole moment:μ(μ_N) = + 0.483(8)Quadrupole moment Q:0.129(4) barn (100 fm²)Nuclear g-factor:g_l = 0.069

Radioactive Decay

Half-life T_½ = 71.5(15) s respectively 7.15 × 10¹ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EE/β⁺	¹⁸⁸Hg	100 %

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
¹⁸⁸Tl		71(2) s	(2-)
^188m2Tl	303.8(2) keV	41(4) ms	9-

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 107) and isobaric (same nucleon number A = 188) with Thallium-188m1. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 107	Isobar A = 188
65	¹⁷²Tb
66	¹⁷³Dy
67	¹⁷⁴Ho
68	¹⁷⁵Er
69	¹⁷⁶Tm
70	¹⁷⁷Yb
71	¹⁷⁸Lu	¹⁸⁸Lu
72	¹⁷⁹Hf	¹⁸⁸Hf
73	¹⁸⁰Ta	¹⁸⁸Ta
74	¹⁸¹W	¹⁸⁸W
75	¹⁸²Re	¹⁸⁸Re
76	¹⁸³Os	¹⁸⁸Os
77	¹⁸⁴Ir	¹⁸⁸Ir
78	¹⁸⁵Pt	¹⁸⁸Pt
79	¹⁸⁶Au	¹⁸⁸Au
80	¹⁸⁷Hg	¹⁸⁸Hg
81	¹⁸⁸Tl	¹⁸⁸Tl
82	¹⁸⁹Pb	¹⁸⁸Pb
83	¹⁹⁰Bi	¹⁸⁸Bi
84	¹⁹¹Po	¹⁸⁸Po
85	¹⁹²At
86	¹⁹³Rn