Thallium-198m2

Properties and data of the isotope ¹⁹⁸Tl.

Content

General data

Name of the isotope:Thallium-198m2; Tl-198m2Symbol:¹⁹⁸Tl or 19881TlMass number A:198 (= number of nucleons)Atomic number Z:81 (= number of protons)Neutrons N:117Isotopic mass:197.970447(8) u (atomic weight of Thallium-198m2)
Excitation energy: 686.8(5) keVNuclide mass:197.926017 u (calculated nuclear mass without electrons)Mass excess:-27.52844 MeVMass defect:1.677175764 u (per nucleus)Nuclear binding energy:1562.27916111 MeV (per nucleus)
7.89029879 MeV (average binding energy per nucleon)Half-life:150(40) nsDecay constant λ:4620981.203733 s^-1Specific activity α:1.412598970558 × 10⁺²⁸ Bq g^-1
3.817835055563 × 10⁺¹⁷ Ci g^-1Spin and parity:
(nuclear angular momentum)(5.7.9)+

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
¹⁹⁸Tl		5.3(5) h	2-
^198m1Tl	543.6(4) keV	1.87(3) h	7+
^198m3Tl	742.4(4) keV	32.1(10) ms	(10-)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 117) and isobaric (same nucleon number A = 198) with Thallium-198m2. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 117	Isobar A = 198
71	¹⁸⁸Lu
72	¹⁸⁹Hf
73	¹⁹⁰Ta
74	¹⁹¹W
75	¹⁹²Re	¹⁹⁸Re
76	¹⁹³Os	¹⁹⁸Os
77	¹⁹⁴Ir	¹⁹⁸Ir
78	¹⁹⁵Pt	¹⁹⁸Pt
79	¹⁹⁶Au	¹⁹⁸Au
80	¹⁹⁷Hg	¹⁹⁸Hg
81	¹⁹⁸Tl	¹⁹⁸Tl
82	¹⁹⁹Pb	¹⁹⁸Pb
83	²⁰⁰Bi	¹⁹⁸Bi
84	²⁰¹Po	¹⁹⁸Po
85	²⁰²At	¹⁹⁸At
86	²⁰³Rn	¹⁹⁸Rn
87	²⁰⁴Fr
88	²⁰⁵Ra
89	²⁰⁶Ac
90	²⁰⁷Th