Astatine (At)
"The Ghost, the rarest hero on Earth, so unstable that it disappears almost as soon as it appears."
A memorable persona to anchor At in your mind.
7
Grams per cm³
300
Celsius (°C)
202
Radius (pm)
Daily Life Link
Astatine has no everyday connection due to its extreme rarity.
Discovery & History
Year Discovered
1940
Discovered By
Dale R. Corson, Kenneth R. MacKenzie & Emilio Segrè
Origin of Name
"The name comes from the Greek ''astatos'', meaning unstable."
Technical Properties
Atomic Mass
[210] u
Standard State
solid
Boiling Point
350°C
Electron Configuration
[Xe] 4f145d106s26p5
1st Ionization Energy
9.5 eV
Electron Affinity
N/A
Oxidation States
"Astatine is a highly radioactive halogen."
Did You Know?
It is the rarest naturally occurring element in the Earth's crust. It is estimated that less than one gram of astatine exists on the entire planet at any given moment.
Its name comes from the Greek word 'astatos', meaning 'unstable', which is appropriate as all of its isotopes are highly radioactive.
It is a halogen, and its properties are predicted to be similar to iodine, but it is so radioactive that it's difficult to study.
If enough could be gathered, it would likely appear as a black or dark metallic solid.