Astatine Element Facts

The chemical element astatine is classed as a halogen and a nonmetal. It was discovered in 1940 by Dale R. Coson, Kenneth Ross Mackenzie and Emilio Segrè.

Actinium can decay to bismuth. Image by Inductiveload. (Ref. 1)
Astatine alpha particle

Data Zone

Classification: Astatine is a halogen and a nonmetal
Color: Presumed very dark
Atomic weight: (210), no stable isotopes
State: solid
Melting point: 302 oC, 575.2 K
Boiling point: 337 oC, 610 K
Electrons: 85
Protons: 85
Neutrons in most abundant isotope: 125
Electron shells: 2,8,18,32,18,7
Electron configuration: [Xe] 4f14 5d10 6s2 6p5
Density @ 20oC: 7 g/cm3 approx.
Show more, including: Heats, Energies, Oxidation, Reactions, Compounds, Radii, Conductivities
Atomic volume: 30 cm3/mol approx.
Structure: unknown
Hardness: mohs
Specific heat capacity
Heat of fusion 6 kJ mol-1 of I2
Heat of atomization 92 kJ mol-1
Heat of vaporization 40 kJ mol-1 of I2
1st ionization energy 890 kJ mol-1
2nd ionization energy
3rd ionization energy
Electron affinity 270 kJ mol-1
Minimum oxidation number -1
Min. common oxidation no. -1
Maximum oxidation number 7
Max. common oxidation no. 1
Electronegativity (Pauling Scale) 2.2
Polarizability volume 6 Å3
Reaction with air
Reaction with 15 M HNO3
Reaction with 6 M HCl
Reaction with 6 M NaOH
Hydride(s) HAt
Atomic radius
Ionic radius (1+ ion)
Ionic radius (2+ ion)
Ionic radius (3+ ion)
Ionic radius (1- ion)
Ionic radius (2- ion)
Ionic radius (3- ion)
Thermal conductivity 1.7 W m-1 K-1
Electrical conductivity
Freezing/Melting point: 302 oC, 575.2 K

5g Coin

The amount of naturally occurring astatine in the world is about 25g. That’s the weight of five United States nickels.

Discovery of Astatine

The first periodic table, produced by Russian chemist Dmitri Mendeleev in 1869, had a space directly underneath iodine. The element to fill this space became known as eka-iodine. This alerted scientists to the possibility that if they looked, they could find the element that would fit into this space.

Many tried to find the new element in nature, but without success.

71 years after Mendeleev published his first periodic table, the element had still not been found, but was instead synthesized in the laboratory using one of the earliest particle accelerators.

Astatine was first produced in 1940 by Dale R. Coson, Kenneth Ross Mackenzie and Emilio Segrè at the University of California, Berkeley.

Segrè, working with Carlo Perrier, had previously synthesized technetium in 1937.(2), (3)

Astatine was made by bombarding bismuth-209 with alpha particles in a cyclotron (particle accelerator) to produce, after emission of two neutrons, astatine-211. The scientists found that the isotope they created was radioactive, so they named the element using the Greek ‘astatos’ meaning unstable.

It is now known that there are no stable astatine isotopes – the longest lived isotope, astatine-210, has a half-life of 8.3 hours. (3)

Three years later, astatine was found in nature by Berta Karlik and Traude Bernert as an intermediate in radioactive decay chains. Traces of the element appear naturally in uranium and thorium minerals as a decay product.

At any given time, about 25 grams of naturally occurring astatine exists on our planet. (3), (4)

Astatine’s Periodic Table Neighborhood

Astatine is the heaviest verified element in Group 17. Like the other halogens, it is a nonmetal, although it shows more metallic character in its chemistry than the others. Astatine and the elements on either side of it, polonium and radon, have no stable isotopes. Too little astatine has ever been present in one place for anyone to actually see it – in fact, since astatine’s boiling point is just 337 oC, any visible quantity of it would be instantly vaporized by the energy released by its rapid radioactive decay.

Appearance and Characteristics

Harmful effects:

Highly radioactive


Astatine is highly radioactive and is only available in tiny quantities. Its properties are inferred from its position in the periodic table and by studying its chemistry in extremely dilute solutions.

Like the other halogens, astatine would be expected to form salts with metals such as sodium. Astatine can also react with hydrogen to form hydrogen astatide, which when dissolved in water, forms hydroastatic acid.

Astatine is the least chemically reactive of the halogens and exhibits the most metallic properties of the halogen group.

Uses of Astatine

Astatine-211 is sometimes used as a radioactive tracer and in cancer treatment.

Like iodine, it is known to accumulate in the thyroid gland.

Abundance and Isotopes

Abundance earth’s crust: About 25 grams exists in Earth’s crust at any given time.

Abundance solar system: negligible

Cost, pure: $ per 100g

Cost, bulk: $ per 100g

Source: Astatine is produced synthetically by bombarding bismuth with alpha particles. It can be obtained naturally from thorium or uranium decay.

Isotopes: More than 30 isotopes of astatine have been identified. All are very short-lived; astatine-210 has the longest half-life of 8 hours 10 minutes.


1. Image: Inductiveload
2. Gurdeep Raj, Advanced Inorganic Chemistry Vol-I, 1998, Krishna Prakashan Media, p344
3. Egon Wiberg, A.F. Holleman, Nils Wiberg, Inorganic Chemistry, 2001, Academic Press, p423
4. B.K. Sharma, Nuclear and Radiation Chemistry, 1997, Krishna Prakashan Media, p147

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  1. I found this extremely useful. Except there was no pricing for my element. Thanks! (;

  2. This was actually really helpful, like the other person said, the only thing is that it has o pricing or the element, other then that this was great. Thanks

  3. very helpful except how can you use it?

  4. This website was very useful but there is no pricing for my element.

  5. It has no pricing because it is not for sale anywhere. Also, it would be a waste of money considering it is highly deadly, being radioactive, and it also decays in 8 hours.