Technetium is a chemical element in the periodic table that has the
symbol Tc and atomic number 43. The chemical properties of this
silvery gray, radioactive, crystalline transition metal are
intermediate between rhenium and manganese. Its short-lived isotope
Tc-99m is used in nuclear medicine to diagnose certain cancers, Tc-99
is used as a gamma ray-free source of beta rays, and its pertechnate
ion could find use as a corrosion preventer for steel (this possible
use is hindered by technetium's radioactivity). Dmitri Mendeleev
predicted many of the properties of element 43, which he called
ekamanganese, well before its actual discovery. In 1937 its isotope
Tc-97 became the first element to be artificially produced, hence its
name (from the Greek technètos, meaning "artificial"). Most technetium
produced on Earth is a by-product of fission of uranium-235 in nuclear
reactors and is extracted from nuclear fuel rods. On earth, technetium
occurs naturally only in uranium ores as a product of spontaneous
fission; the quantities are infinitesimal but have been measured.
Read the rest of this article:
http://en.wikipedia.org/wiki/Technetium
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Today's selected anniversaries:
455:
The Vandals plundered Rome.
(
http://en.wikipedia.org/wiki/Vandals)
1800:
The first smallpox vaccination was administered in North America.
(
http://en.wikipedia.org/wiki/smallpox)
1865:
Forces under General Edmund Kirby Smith became the last Confederate
army to surrender in the American Civil War.
(
http://en.wikipedia.org/wiki/Edmund_Kirby_Smith)
1946:
Birth of the Italian Republic: Italy became a republic and abolished
the monarchy, exiling Umberto.
(
http://en.wikipedia.org/wiki/Birth_of_the_Italian_Republic)
1953:
Coronation of Queen Elizabeth II of the United Kingdom, the first to
be televised.
(
http://en.wikipedia.org/wiki/Elizabeth_II_of_the_United_Kingdom)
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Wikiquote of the day:
"I'm the guy they used to call Deep Throat." -- W. Mark Felt
(
http://en.wikiquote.org/wiki/W._Mark_Felt)