Thallium-200

Properties and data of the isotope ²⁰⁰Tl.

Content

General data

Name of the isotope:Thallium-200; Tl-200Symbol:²⁰⁰Tl or 20081TlMass number A:200 (= number of nucleons)Atomic number Z:81 (= number of protons)Neutrons N:119Isotopic mass:199.970964(6) u (atomic weight of Thallium-200)Nuclide mass:199.926534 u (calculated nuclear mass without electrons)Mass excess:-27.04686 MeVMass defect:1.693988596 u (per nucleus)Nuclear binding energy:1577.94021324 MeV (per nucleus)
7.88970107 MeV (average binding energy per nucleon)Separation energy:S_N = 7.059(6) MeV (first neutron)
S_P = 4.790(6) MeV (first proton)Half-life:26.1(1) hDecay constant λ:7.377045344401 × 10^-6 s^-1Specific activity α:2.232442522317 × 10⁺¹⁶ Bq g^-1
603362.84386968 Ci g^-1Spin and parity:
(nuclear angular momentum)2-Magnetic dipole moment:μ(μ_N) = 0.04(1)Nuclear g-factor:g_l = 0.02Charge radius:5.4491(31) femtometer fmYear of discovery:1949

Radioactive Decay

Half-life T_½ = 26.1(1) h (hours) respectively 9.3960 × 10⁴ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EE/β⁺	²⁰⁰Hg	100 %	2.456(6) MeV

Parent Nuclides

Direct parent isotope is: ²⁰⁰Pb.

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
^200m1Tl	753.60(24) keV	34.0(9) ms	7+
^200m2Tl	762.00(24) keV	0.33(5) μs	5+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 119) and isobaric (same nucleon number A = 200) with Thallium-200. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 119	Isobar A = 200
73	¹⁹²Ta
74	¹⁹³W
75	¹⁹⁴Re
76	¹⁹⁵Os	²⁰⁰Os
77	¹⁹⁶Ir	²⁰⁰Ir
78	¹⁹⁷Pt	²⁰⁰Pt
79	¹⁹⁸Au	²⁰⁰Au
80	¹⁹⁹Hg	²⁰⁰Hg
81	²⁰⁰Tl	²⁰⁰Tl
82	²⁰¹Pb	²⁰⁰Pb
83	²⁰²Bi	²⁰⁰Bi
84	²⁰³Po	²⁰⁰Po
85	²⁰⁴At	²⁰⁰At
86	²⁰⁵Rn	²⁰⁰Rn
87	²⁰⁶Fr	²⁰⁰Fr
88	²⁰⁷Ra
89	²⁰⁸Ac
90	²⁰⁹Th