The Element Astatine


Astatine occurs naturally in three natural radioactive decay series. However due to its short half life, it is found only in small amounts. It is the rarest naturally-occurring element, with the total amount in Earth's crust estimated to be less than 1 oz (28 g) at any given time. Astatine is classified as a halogen and is known to possibly accumulate in the thyroid like iodine.

Renowned as one of the long lived isotopes, Astatine-210 has a half a half life of only 8.3 hours. There are another 20 or so isotopes of astatine that have been identified all of which are known to be radioactive.

Atomic Number & Chemical Properties


Element Basics:

Chemical Symbol: At
Atomic Number: 85
Atomic Weight: 209.9871
Element Classification: Halogen
Discovered By: D.R.Corson, K.R.MacKenzie, E. Segre
Date of Discovery: 1940 (United States)
Origin of Name: Greek: astatos (unstable).

How to Recognize it at a Party:

Unstable, radioactive halogen

Seriously Atomic Information:

Density (g/cc): n/a
Melting Point (°K): 575
Boiling Point (°K): 610
Atomic Radius (pm): n/a
Atomic Volume (cc/mol): n/a
Covalent Radius (pm): (145)
Ionic Radius: 62 (+7e)
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

Getting Intimate with Astatine:

Lattice Structure: n/a
Lattice Constant (Å): n/a
Lattice C/A Ratio: n/a
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


Society's Questions About Astatine:

Have you ever wondered what everyone else in the world thinks about Astatine? Is anyone else looking for it too? If so, why? What do they want?

The following list shows the most common online questions about the element Astatine. Are your questions the same or different from everyone else's?

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