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THE MINERAL REALGAR, IS COMPOSED OF THE ELEMENTS OF ARSENIC AND SULFUR.
IT IS A MAJOR SOURCE OF ARSENIC. Arsenic is a metallic chemical element in
Group VA of the periodic table. Its symbol is As, its atomic number
33, and its atomic weight 74.9216. The Earth's crust contains only
about 5.5 parts arsenic per million. Arsenic occurs in numerous
minerals, in particular realgar, orpiment,
and arsenopyrite. Arsenic and some arsenic compounds have been known
for a long time. Aristotle thought that arsenic was a kind of
sulfur. In about 1250, Albertus Magnus became the first to describe
a method of manufacturing arsenic. Since then the method has
scarcely changed: the mineral arsenopyrite is heated and decomposes
with the liberation of arsenic gas. The gas can be condensed on a
cold surface.
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