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Astatine-220

Properties and data of the isotope 220At.

 

See also: list of Astatine isotopes.

 

General data

Name of the isotope:Astatine-220; At-220Symbol:220AtMass number A:220Atomic number Z:85 (= number of protons)Neutrons N:135Isotopic mass:220.015433(15) u (atomic weight of Astatine-220)Nuclide mass:219.9688093 u (calculated nuclear mass without electrons)Mass excess:14.37575 MeVMass defect:1.81945838 u (per nucleus)Nuclear binding energy:1694.81456422 MeV (per nucleus)
7.70370256 MeV (average binding energy per nucleon)
Separation energy:SN = 4.092(14) MeV (first neutron)
SP = 5.595(21) MeV (first proton)
Half-life:3.71(4) minDecay constant λ:0.0031138687356691 s-1Spin and parity:3Year of discovery:1989

 

Radioactive Decay

Half-life T½ = 3.71(4) min (minutes) respectively 2.226 × 102 seconds s.

Decay modeDaughterProbabilityDecay energyγ energy
(intensity)
α216Bi8(2) %6,077(18) MeV
β-220Rn92(2) %3,764(14) MeV

 

Astatine-220 decay chain

 

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 135) and isobaric (same nucleon number A = 220) with Astatine-220. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

 

OZIsotone N = 135Isobar A = 220
80215Hg
81216Tl
82217Pb220Pb
83218Bi220Bi
84219Po220Po
85220At220At
86221Rn220Rn
87222Fr220Fr
88223Ra220Ra
89224Ac220Ac
90225Th220Th
91226Pa220Pa
92227U220U
93228Np
94229Pu
95230Am

 

External data and identifiers

Adopted Levels, Gammas:NuDat 220At

 


Category: Isotopes

Last update: 26.11.2022



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