Astatine: the essentials

The longest-lived isotope, 210At, has a half-life of only 8.3 hours. There are about 20 isotopes known, all of which are radioactive. Astatine is a halogen and possibly accumulates in the thyroid like iodine.

astatine
This sample of uranite contains a vanishingly small amount of astatine. Image adapted with permission from Prof James Marshall's (U. North Texas, USA) Walking Tour of the elements CD.

Astatine: historical information

Astatine was discovered by Dale Corson, MacKenzie, Segre in 1940 at California, USA. Origin of name: from the Greek word "astatos" meaning "unstable".

Astatine ynthesized in 1940 by Dale Corson and others at the University of California, USA, by bombarding bismuth (209Bi) with α-particles.

Astatine around us Read more »

Astatine has no biological role.

Astatine is not found in any significant quantity in the geosphere. Some isotopes of astatine (215At, 218At and 219At) are present in uranium and thorium minerals as part of radiodecay series. The total amount present in the Earth's crust is probably less than 30 g at any one time.

Abundances for cobalt in a number of different environments. More abundance data »
Location ppb by weight ppb by atoms Links
Universe (no data) (no data) Chemical elements abundance by weight in the universe on a miniature periodic table spark table
Crustal rocks (no data) (no data) Chemical elements abundance by weight in the earth's crust on a miniature periodic table spark table
Human (no data) ppb by weight (no data) atoms relative to C = 1000000 Chemical elements abundance by weight in humans on a miniature periodic table spark table

Physical properties Read more »

Heat properties Read more »

Crystal structure Read more »

The solid state structure of astatine is: .

Astatine: orbital properties Read more »

Astatine atoms have 85 electrons and the shell structure is 2.8.18.32.18.7. The ground state electronic configuration of neutral Astatine is [Xe].4f14.5d10.6s2.6p5 and the term symbol of Astatine is 2P3/2.

Isolation

Isolation: astatine is radioactive and essentially unavailable in nature. It is not possible to make other than in a nuclear reactor. Bombardment of the bismuth isotope 20983Bi with α-particles (helium nuclei, 42He) results in formation of shortlived astatine and neutrons. The bismuth target is cooled during irradiation to prevent the volatile astatine disappearing.

20983Bi + 42He → 21185At + 2 10n

The 211At isotope has a half life of just over 7 hours so it is necessary to work quickly with it! Available quantities are of the order of 0.001 mg.

Heating the bismuth target to 300-600°C under N2 results in a stream of the elemental astatine that can be collected on a cold glass finger.

Astatine isotopes Read more »

Table. Stables isotopes of cobalt.
Isotope Mass
/Da
Natural
abund.
(atom %)
Nuclear
spin (I)
Nuclear
magnetic
moment (μ/μN)
nil

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