|
|
Atomic Number: |
33 |
Melting Point: | ~817 ºC | |
| Atomic Symbol: | As | Boiling Point: | 603 ºC (sublimation) | ||
| Atomic Weight: | 74.9216 amu | Density: | 5727
kg/m 3 |
||
| Atomic Radius: |
125 pm |
Oxidation States: | 5, 3, -3 | ||
| Covalent Radius: | 119 pm | Electron Configuration: | [Ar]4s23d104p3 | ||
| van der Waals Radius: |
185 pm |
State of Matter: | solid |
(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) 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.
The element is a steel gray, very brittle, crystalline, semimetallic solid; it tarnishes in air, and when it is heated it rapidly oxidizes to arsenous oxide, which smells of garlic. Elemental arsenic occurs in two solid modifications: yellow, and gray or metallic, with specific gravities of 1.97, and 5.73, respectively. Arsenic and its compounds are poisonous.
It is sometimes found native, but usually combined with silver, cobalt, nickel, iron, antimony, or sulfur. Arsenopyrite also called mispickel is the most common mineral from which, on heating, the arsenic sublimes leaving ferrous sulfide.
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. It is an important semiconductor material, used in integrated circuits. Circuits made using the compound are much faster (but also much more expensive) than those made in silicon.
Arsenic trioxide has been used in hematology to treat patients with acute promyelocytic leukemia that are resistant to ATRA treatment. It is also used in Australia for treating termite infestations in houses and various agricultural insecticides and poisons.Arsenic has only one stable isotope with one hundred percent natural abundance.
Arsenic and many of its compounds are especially potent poisons. Arsenic kills by massively disrupting the digestive system, leading to death from shock.
