Symbol: At
Atomic Number: 85
Atomic Weight: 209.9871
Element Classification: Halogen
Discovered By: D.R.Corson, K.R.MacKenzie, E. Segre
Discovery Date: 1940 (United States)
Name Origin: Greek: astatos (unstable).
Density (g/cc): n/a
Melting Point (K): 575
Boiling Point (K): 610
Appearance: Unstable, radioactive halogen
Atomic Radius (pm): n/a
Atomic Volume (cc/mol): n/a
Covalent Radius (pm): (145)
Ionic Radius: 62 (+7e)
Specific Heat (@20°C J/g mol): n/a
Fusion Heat (kJ/mol): n/a
Evaporation Heat (kJ/mol): n/a
Thermal Conductivity (@25°C W/m K):
Debye Temperature (K): n/a
Pauling Negativity Number: 2.2
First Ionizing Energy (kJ/mol): 916.3
Oxidation States: 7, 5, 3, 1, -1
Electronic Configuration: [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁵
Lattice Structure: n/a
Lattice Constant (Å): n/a
Lattice C/A Ratio: n/a