Thallium-202m

Properties and data of the isotope ^202mTl.

Contents

See also: List of individual Thallium isotopes (and general data sources).

General data

Name of the isotope:Thallium-202m; Tl-202mSymbol:^202mTl or 202m81TlMass number A:202 (= number of nucleons)Atomic number Z:81 (= number of protons)Neutrons N:121Nucleon pairing (Z - N):odd - oddNuclear ratio (N/Z ratio):1.4938271604938 (= neutron-proton ratio)Neutron excess (N-Z):40Excitation energy:950.19(10) keVIsotopic mass:201.9721091(17) u (atomic weight of Thallium-202m)Nuclide mass:201.9276791 u (calculated nuclear mass without electrons)Mass excess:-25.98021 MeVMass defect:1.710173328 u (per nucleus)Nuclear binding energy:1593.01619399 MeV (per nucleus)
7.88621878 MeV (average binding energy per nucleon)Half-life:591(3) μsDecay constant λ:1172.8378689678 s^-1Specific activity α:3.513927787458 × 10⁺²⁴ Bq g^-1
94971021282665 Ci g^-1Spin and parity:
(nuclear angular momentum)7+Magnetic dipole moment:μ(μ_N) = + 0.90(4)Nuclear g-factor:g_l = 0.12857142857143

Radioactive Decay

Half-life T_½ = 591(3) μs respectively 5.91 × 10^-4 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
Iso	²⁰²Tl	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
²⁰²Tl		12.31(8) d	2-

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 121) and isobaric (same nucleon number A = 202) with Thallium-202m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 121	Isobar A = 202
73	¹⁹⁴Ta
74	¹⁹⁵W
75	¹⁹⁶Re
76	¹⁹⁷Os	²⁰²Os
77	¹⁹⁸Ir	²⁰²Ir
78	¹⁹⁹Pt	²⁰²Pt
79	²⁰⁰Au	²⁰²Au
80	²⁰¹Hg	²⁰²Hg
81	²⁰²Tl	²⁰²Tl
82	²⁰³Pb	²⁰²Pb
83	²⁰⁴Bi	²⁰²Bi
84	²⁰⁵Po	²⁰²Po
85	²⁰⁶At	²⁰²At
86	²⁰⁷Rn	²⁰²Rn
87	²⁰⁸Fr	²⁰²Fr
88	²⁰⁹Ra	²⁰²Ra
89	²¹⁰Ac
90	²¹¹Th
91	²¹²Pa