Thorium-212
Properties and data of the isotope 212Th.
See also: list of Thorium isotopes.
General data
Name of the isotope:Thorium-212; Th-212Symbol:212Th or 21290ThMass number A:212 (= number of nucleons)Atomic number Z:90 (= number of protons)Neutrons N:122Isotopic mass:212.013001(11) u (atomic weight of Thorium-212)Nuclide mass:211.9636352 u (calculated nuclear mass without electrons)Mass excess:12.11035 MeVMass defect:1.748371632 u (per nucleus)Nuclear binding energy:1628.59768498 MeV (per nucleus)
7.68206455 MeV (average binding energy per nucleon)Separation energy:SN = 9.87(7) MeV (first neutron)
SP = 2.38(5) MeV (first proton)Half-life:31.7(13) msDecay constant λ:21.865841658042 s-1Specific activity α:6.211282004047 × 10+22 Bq g-1
1678724865958.8 Ci g-1Spin and parity:
(nuclear angular momentum)0+Year of discovery:1980
Radioactive Decay
Half-life T½ = 31.7(13) ms respectively 3.17 × 10-2 seconds s.
Decay mode | Daughter | Probability | Decay energy | γ energy (intensity) |
---|
α | 208Ra | ca. 99.7 % | 7.958(5) MeV | |
EE/β+ | 212Ac | ca. 0.3 % | 4.83(5) MeV | |
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 122) and isobaric (same nucleon number A = 212) with Thorium-212. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
OZ | Isotone N = 122 | Isobar A = 212 |
74 | 196W | |
75 | 197Re | |
76 | 198Os | |
77 | 199Ir | |
78 | 200Pt | |
79 | 201Au | |
80 | 202Hg | 212Hg |
81 | 203Tl | 212Tl |
82 | 204Pb | 212Pb |
83 | 205Bi | 212Bi |
84 | 206Po | 212Po |
85 | 207At | 212At |
86 | 208Rn | 212Rn |
87 | 209Fr | 212Fr |
88 | 210Ra | 212Ra |
89 | 211Ac | 212Ac |
90 | 212Th | 212Th |
91 | 213Pa | 212Pa |
92 | 214U | |
External data and identifiers
Last update: 2020-10-23
Perma link: https://www.chemlin.org/isotope/thorium-212
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