Astatine

Non-Metal

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

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Electronic 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: --

Thermal data

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

Steric data

Atomic radius: 1.43 Å
Ionic radius: -- Å
Covalent radius: 1.45 Å
Atomic volume: -- cm³/mol
Density (293 K): -- g/cm³
Crystal structure: --

Nuclide	Mass	Spin	Halflife	Decay mode	Decay tree
²⁰⁶At	206	5	29.4m	EC, β+, α	View
²⁰⁸At	208	6	1.63h	EC, β+, α	View
²¹¹At	210.988	9/2	7.21h	EC, α	View
²¹⁵At	214.999	9/2	0.10ms	α	View
²¹⁷At	217.005	9/2	32ms	α, β-	View
²¹⁸At	218.009	0	1.6s	α	View
²¹⁹At	219.011	0	50s	α, β-	View

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.

Astatine

Physical data

Electronic data

Thermal data

Steric data

Isotopes

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