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Forget chocolate melting in your hands, try Gallium. Its a
strange metal that has a melting point at 85 °F. Pick up a solid piece of
gallium and squeeze it in your hand for a few minutes. Soon, you’ll have a
liquid puddle of metal jiggling in your hand. Scientists love to show off
experiments with Gallium. Set a drop on an aluminum can and watch it slowly
turn the aluminum into brittle tissue paper. Set the stuff in sulfuric acid and
you’ll see it start beating like a heart. Dmitri Mendeleyev first predicted
Gallium and placed it in the Period Table before it was officially discovered
in 1875.
Gallium is a chemical element with symbol Ga and atomic
number 31. Elemental gallium does not occur in free form in nature, but as
the gallium(III) compounds that are in trace amounts in zinc ores and in
bauxite. Gallium is a soft silvery metal, and elemental gallium is a brittle
solid at low temperatures. If it is held in the human hand long enough, gallium
will melt, since it melts at the temperature of about 29.76 °C
(85.57 °F) (slightly above room temperature). The melting point of gallium
is used as a temperature reference point. The alloy galinstan (68.5% gallium,
21.5% indium, and 10% tin) has an even lower melting point of −19 °C
(−2 °F), well below the freezing point of water. Beginning with its
discovery in 1875 through the era of semiconductors, gallium was used primarily
as an agent to make alloys that melt at low temperatures. Then, gallium became
useful in semiconductors, including as a dopant.
Today, nearly all gallium is used in electronics. Gallium
arsenide, the primary chemical compound of gallium in electronics, is used in
microwave circuits, high-speed switching circuits, and infrared circuits.
Gallium nitride and indium gallium nitride, minority semiconductor uses,
produce blue and violet light-emitting diodes (LEDs) and diode lasers.
Gallium has no known role in biology. Because gallium(III)
and ferric salts behave similarly in biological systems, gallium ions often
mimic iron ions in medical applications. Some pharmaceuticals containing
gallium and radiopharmaceuticals have been used rarely.
Wikipedia.org
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