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Astatine

Non-Metal radioactivesolid
Symbol: At
Atomic number: 85
Atomic mass: (209.9871)
Group: Halogen
CAS-number: 7440-68-8

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Physical data
Isotopes
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Physical data

Electronic dataThermal dataSteric data
Shells: 2, 8, 18, 32, 18, 7
Orbitals: [Xe] 4f14 5d10 6s2 6p5
Electronegativity: 2.2, 2.0
1. Ionization potential: 9.5 eV
2. Ionization potential: -- eV
3. Ionization potential: -- eV
Oxidation states: 7, 5, 3, 1, -1
Electrical conductivity: --
Melting point: 302 °C
Boiling point: 337 °C
Specific heat: -- J/gK
Heat of fusion: -- kJ/mol
Heat of vaporization: -- kJ/mol
Thermal conductivity: 0.017 W/cmK
Atomic radius: 1.43 Å
Ionic radius: -- Å
Covalent radius: 1.45 Å
Atomic volume: -- cm³/mol
Density (293 K): -- g/cm³
Crystal structure: --

Isotopes

NuclideAbundance [%]MassSpinHalflifeDecay modeDecay tree
206At 0 206 5 29.4m EC, β+, α View
208At 0 208 6 1.63h EC, β+, α View
211At 0 210.988 9/2 7.21h EC, α View
215At 0 214.999 9/2 0.10ms α View
217At 0 217.005 9/2 32ms α, β- View
218At 0 218.009 0 1.6s α View
219At 0 219.011 0 50s α, β- View

Other info

Name origin:Greek: astatos (unstable).
Description:Unstable, radioactive member of the halogen group.
Discovered by:D.R.Corson, K.R.MacKenzie, E.Segré
Year:1940
Place:United States
Sources:Does not occur in nature. Similar to iodine. Produced by bombarding bismuth with alpha particles.
Use(s):Since its isotopes have such short half-lives there are no commercially significant compounds of astatine.