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Astatine Non-
metal
Solid Radio
active
Symbol: At
Atomic number: 85
Atomic mass: (209.9871)
Group: Halogen
CAS-number: 7440-68-8
 
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I
Po At Rn
 

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Physical data

Electronic data  Thermal data  Steric data
Shells: 2,8,18,32,18,7
Orbitals: [Xe] 4f14 5d10 6s2 6p5
Electronegativity: 2.0, 2.2
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: --
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Isotopes

NuclideAbundance [%]MassSpinHalflifeDecay modeDecay tree
206At0206529.4mEC,Beta+,AlphaView
208At020861.63hEC,Beta+,AlphaView
211At0210.9889/27.21hEC,AlphaView
215At0214.9999/20.10msAlphaView
217At0217.0059/232msAlpha,Beta-View
218At0218.00901.6sAlphaView
219At0219.011050sAlpha,Beta-View
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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.
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