Astatine-212m1
Properties and data of the isotope 212At.
See also: list of Astatine isotopes.
General data
Name of the isotope:Astatine-212m1; At-212m1Symbol:212At or 21285AtMass number A:212 (= number of nucleons)Atomic number Z:85 (= number of protons)Neutrons N:127Isotopic mass:211.9907372(26) u (atomic weight of Astatine-212m1)
Excitation energy: 223(7) keVNuclide mass:211.9441135 u (calculated nuclear mass without electrons)Mass excess:-8.62824 MeVMass defect:1.774834852 u (per nucleus)Nuclear binding energy:1653.24801563 MeV (per nucleus)
7.7983397 MeV (average binding energy per nucleon)Half-life:119(3) msDecay constant λ:5.8247662231928 s-1Specific activity α:1.662443728543 × 10+22 Bq g-1
449309115822.57 Ci g-1Spin and parity:
(nuclear angular momentum)(9-)
Radioactive Decay
Half-life T½ = 119(3) ms respectively 1.19 × 10-1 seconds s.
Decay mode | Daughter | Probability | Decay energy | γ energy (intensity) |
---|
α | 208Bi | > 99 % | | |
Iso | 212At | ≤ 1 % | | |
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 |
---|
212At | | 314(2) ms | (1-) |
212m2At | 4771.6(11) keV | 152(5) μs | (25-) |
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 127) and isobaric (same nucleon number A = 212) with Astatine-212m1. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
OZ | Isotone N = 127 | Isobar A = 212 |
76 | 203Os | |
77 | 204Ir | |
78 | 205Pt | |
79 | 206Au | |
80 | 207Hg | 212Hg |
81 | 208Tl | 212Tl |
82 | 209Pb | 212Pb |
83 | 210Bi | 212Bi |
84 | 211Po | 212Po |
85 | 212At | 212At |
86 | 213Rn | 212Rn |
87 | 214Fr | 212Fr |
88 | 215Ra | 212Ra |
89 | 216Ac | 212Ac |
90 | 217Th | 212Th |
91 | 218Pa | 212Pa |
92 | 219U | |
External data and identifiers
Last update: 2020-10-23
Perma link: https://www.chemlin.org/isotope/astatine-212m1
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