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The Epic Interactive Encyclopedia 1998
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Epic Interactive Encyclopedia, The - 1998 Edition (1998)(Epic Marketing).iso
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Potassium
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1992-09-02
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Metallic element of the alkali group, symbol
K, atomic number 19, relative atomic mass
39.1. It is a soft, silvery-bright metal
which reacts violently with water, forming
potassium hydroxide and hydrogen; this
ignites and burns spontaneously with a violet
flame. The element is therefore kept under
kerosene or naphtha. The salts are important
as essential constituents of fertilizers.
Alloyed with sodium, it may be used as a
coolant in nuclear reactors. Widely
distributed in nature in combination with
other elements, it is found in salt deposits
(carnallite and kainite) and minerals
(feldspar, greensand, alunite, leucite), and
forms 2.9% of the Earth's solid crust. It was
discovered 1807 by Humphrey Davy by
electrolysis of caustic potash (KOH), the
first instance of a metal being isolated by
an electric current.