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Atomic Number: 33
Atomic Symbol: As
Atomic Weight: 74.9216
Electron Configuration: [Ar]4s23d104p3
History
(L. arsenicum, Gr. arsenikon, yellow orpiment, identified with
arenikos, male, from the belief that metals were different sexes; Arabic,
Az-zernikh, the orpiment from Persian zerni-zar, gold) Elemental arsenic occurs
in two solid modifications: yellow, and gray or metallic, with specific
gravities of 1.97, and 5.73, respectively. It is believed that Albertus Magnus
obtained the element in 1250 A.D. In 1649 Schroeder published two methods of
preparing the element. Mispickel, arsenopyrite, (FeSAs) is the most common
mineral from which, on heating, the arsenic sublimes leaving ferrous sulfide.
Properties
The element is a steel gray, very brittle, crystalline, semimetallic
solid; it tarnishes in air, and when heated is rapidly oxidized to arsenous
oxide with the odor of garlic. Arsenic and its compounds are poisonous.
Uses
Arsenic is used in bronzing, pyrotechny, and for hardening and
improving the sphericity of shot. The most important compounds are white
arsenic, the sulfide, Paris green, calcium arsenate, and lead arsenate; the last
three have been used as agricultural insecticides and poisons. Marsh's test
makes use of the formation and ready decomposition of arsine. Arsenic is finding
increasing uses as a doping agent in solid-state devices such as transistors.
Gallium arsenide is used as a laser material to convert electricity directly
into coherent light.
Sources: CRC Handbook of Chemistry and
Physics and the American Chemical Society.
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