What is "arsenic"

Arsenic \Ar"se*nic\ ([aum]r"s[-e]*n[i^]k; 277), n. [L. arsenicum, Gr. 'arseniko`n, 'arreniko`n, yellow orpiment, perh. fr. 'arseniko`s or better Attic 'arreniko`s masculine, 'a`rrhn male, on account of its strength, or fr. Per. zern[=i]kh: cf. F. arsenic.]

1. (Chem.) One of the elements, a solid substance resembling a metal in its physical properties, but in its chemical relations ranking with the nonmetals. It is of a steel-gray color and brilliant luster, though usually dull from tarnish. It is very brittle, and sublimes at 356[deg] Fahrenheit. It is sometimes found native, but usually combined with silver, cobalt, nickel, iron, antimony, or sulphur. Orpiment and realgar are two of its sulphur compounds, the first of which is the true arsenicum of the ancients. The element and its compounds are active poisons. Specific gravity from 5.7 to 5.9. Atomic weight 75. Symbol As.

2. (Com.) Arsenious oxide or arsenious anhydride; -- called also arsenious acid, white arsenic, and ratsbane.

Arsenic \Ar*sen"ic\, a. (Chem.) Pertaining to, or derived from, arsenic; -- said of those compounds of arsenic in which this element has its highest equivalence; as, arsenic acid.

late 14c., from Old French arsenic, from Latin arsenicum, from late Greek arsenikon "arsenic" (Dioscorides; Aristotle has it as sandarake), adapted from Syriac (al) zarniqa "arsenic," from Middle Persian zarnik "gold-colored" (arsenic trisulphide has a lemon-yellow color), from Old Iranian *zarna- "golden," from PIE root *ghel- (2) "to shine," with derivatives referring to bright materials and gold (see glass).\n

\nThe form of the Greek word is folk etymology, literally "masculine," from arsen "male, strong, virile" (compare arseno-koites "lying with men" in New Testament) supposedly in reference to the powerful properties of the substance. The mineral (as opposed to the element) is properly orpiment, from Latin auri pigmentum, so called because it was used to make golden dyes.

a. Of, or containing arsenic with a valence of 5. n. 1 A nonmetallic chemical element (''symbol'' As) with an atomic number of 33. 2 arsenic trioxide.

1. n. a very poisonous metallic element that has three allotropic forms; arsenic and arsenic compounds are used as herbicides and insecticides and various alloys; found in arsenopyrite and orpiment and realgar [syn: As, atomic number 33]

2. a white powdered poisonous trioxide of arsenic; used in manufacturing glass and as a pesticide and weed killer [syn: arsenic trioxide, arsenous anhydride, arsenous oxide]

Arsenic is a chemical element with symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, but only the gray form is important to industry.

The primary use of metallic arsenic is in alloys of lead (for example, in car batteries and ammunition). Arsenic is a common n-type dopant in semiconductor electronic devices, and the optoelectronic compound gallium arsenide is the second most commonly used semiconductor after doped silicon. Arsenic and its compounds, especially the trioxide, are used in the production of pesticides, treated wood products, herbicides, and insecticides. These applications are declining, however.

A few species of bacteria are able to use arsenic compounds as respiratory metabolites. Trace quantities of arsenic are an essential dietary element in rats, hamsters, goats, chickens, and presumably many other species, including humans. However, arsenic poisoning occurs in multicellular life if quantities are larger than needed. Arsenic contamination of groundwater is a problem that affects millions of people across the world.