Atomic number 85
Astatine
Halogen
No photo: here’s why
Astatine is the rarest naturally occurring element. It is so radioactive that any visible amount would instantly boil away in its own heat - no one has ever seen it.
Quick facts
- Atomic mass
- 210.00
- Group
- 17
- Period
- 6
- State (STP)
- unknown
- Electronegativity
- 2.20
- Common ox. states
- -1, +1, +3, +5, +7
Properties
[Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁵
- Ionization energy
- 899.0 kJ/mol
- Electron affinity
- 233.0 kJ/mol
- Melting point
- 575.00 K (301.9 °C)
- Boiling point
- 610.00 K (336.9 °C)
How dangerous is it?
One of the rarest elements on Earth, made only in tiny trace amounts in labs. It is intensely radioactive and never exists in any amount you could see.
- RadioactiveImmediate
It gives off intense radiation as it decays, and it breaks down so fast that even a small amount would be fiercely active. (it exists only as fleeting trace amounts, never a visible sample)
Produced and studied only in trace quantities inside shielded research facilities.
How it bonds
Astatine is the rarest naturally occurring element on Earth (less than 30 g exists in the entire crust at any time). Predicted to behave like iodine - one bond, 3 lone pairs - but no one has ever seen a macroscopic amount. All isotopes are radioactive with short half-lives.
