ASTATINE is the rarest naturally occurring element known on Earth. The total amount estimated to be apparent at any given time in the Earth;s crust is 28 grams (1 oz). The rarity of this element is explained by the fact that there has been no astatine left since the Earth's creation. All of the astatine on Earth today is the result of decay of the heavier elements.
Astatine is a radioactive chemical element. Its symbol on the periodic table is At, and its atomic number is 85. Very little is known about this rare element, as it only occurs as a result of the decay of the heavy elements, and itself decays very quickly. Research into the element has however shown that it follows periodic conventions in that it is the heaviest known halogen, with melting and boiling points being higher than those of lighter halogens. It is known to form ionic astatides like those lighter halogens, as well as positive oxidation states. The biggest difference between astatine and iodine is found in the fact that in the HAt molecule, the negative charge is transferred to hydrogen rather than astatine.
The element was first produced and therefore discovered by Dale R. Corson, Kenneth Ross MacKenzie and Emilio Segrè in 1940. It took at least three years before naturally occurring astatine was found in natural minerals on Earth. It has been until only recently that the physical and chemical characteristics of the element were ultimately inferred from comparison with other elements. Some isotopes of astatine have been used as alpha-particle emitters in science, and various incarnations of medical applications for astatine-211 have been tested.
Astatine is a radioactive chemical element. Its symbol on the periodic table is At, and its atomic number is 85. Very little is known about this rare element, as it only occurs as a result of the decay of the heavy elements, and itself decays very quickly. Research into the element has however shown that it follows periodic conventions in that it is the heaviest known halogen, with melting and boiling points being higher than those of lighter halogens. It is known to form ionic astatides like those lighter halogens, as well as positive oxidation states. The biggest difference between astatine and iodine is found in the fact that in the HAt molecule, the negative charge is transferred to hydrogen rather than astatine.
The element was first produced and therefore discovered by Dale R. Corson, Kenneth Ross MacKenzie and Emilio Segrè in 1940. It took at least three years before naturally occurring astatine was found in natural minerals on Earth. It has been until only recently that the physical and chemical characteristics of the element were ultimately inferred from comparison with other elements. Some isotopes of astatine have been used as alpha-particle emitters in science, and various incarnations of medical applications for astatine-211 have been tested.