Thallium-212

Properties and data of the isotope ²¹²Tl.

Content

General data

Name of the isotope:Thallium-212; Tl-212Symbol:²¹²Tl or 21281TlMass number A:212 (= number of nucleons)Atomic number Z:81 (= number of protons)Neutrons N:131Isotopic mass:211.99833(21) u (atomic weight of Thallium-212)Nuclide mass:211.9539 u (calculated nuclear mass without electrons)Mass excess:-1.55559 MeVMass defect:1.770601588 u (per nucleus)Nuclear binding energy:1649.30475561 MeV (per nucleus)
7.77973941 MeV (average binding energy per nucleon)Separation energy:S_N = 3.54(20) MeV (first neutron)
S_P = 8.22(28) MeV (first proton)Half-life:ca. 96 sDecay constant λ:0.0072202831308328 s^-1Specific activity α:2.060737538507 × 10⁺¹⁹ Bq g^-1
556956091.48841 Ci g^-1Spin and parity:
(nuclear angular momentum)(5+)Year of discovery:1998

Radioactive Decay

Half-life T_½ = ca. 96 s respectively 9.6 × 10¹ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	²¹²Pb		6.0(2) MeV
β^-, n	²¹¹Pb		0.87(20) MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 131) and isobaric (same nucleon number A = 212) with Thallium-212. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 131	Isobar A = 212
79	²¹⁰Au
80	²¹¹Hg	²¹²Hg
81	²¹²Tl	²¹²Tl
82	²¹³Pb	²¹²Pb
83	²¹⁴Bi	²¹²Bi
84	²¹⁵Po	²¹²Po
85	²¹⁶At	²¹²At
86	²¹⁷Rn	²¹²Rn
87	²¹⁸Fr	²¹²Fr
88	²¹⁹Ra	²¹²Ra
89	²²⁰Ac	²¹²Ac
90	²²¹Th	²¹²Th
91	²²²Pa	²¹²Pa
92	²²³U