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| Atomic Number: | 33 | Atomic Symbol: | As | | Atomic Weight: | 74.9216 | Electron Configuration: | 2-8-18-5 | | Shells: | 2,8,18,5 | Filling Orbital: | 4p3 | | Melting Point: | 817 @ 28 atm.oC | Boiling Point: | sublimes @ 613oC | | Uses: | LEDs, deadly poison, semiconductors |
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)
SourcesElemental 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.
PropertiesThe 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.
HandlingArsenic and its compounds are poisonous.
Arsenic is used in
bronzing, pyrotechny, and for hardening and improving the sphericity of shot.
CompoundsThe 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.
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