Arsenic is a chemical element that has the symbol As and atomic number 33. Its Atomic Mass is 74.92. Its Ionic Charge is (3-). This is a notoriously poisonous metalloid that has many allotropic forms: yellow (molecular non-metallic) and several black and gray forms (metalloids) are a few that are seen. Three metalloidal forms of arsenic with different crystal structures are found free in nature (the minerals arsenic sensu strictu and the much rarer arsenolamprite and pararsenolamprite), but it is more commonly found as arsenide and arsenate compounds. Several hundred such mineral species are known. Arsenic and its compounds are used as pesticides, herbicides, insecticides and various alloys.

The most common oxidation states for arsenic are -3 (arsenides: usually alloy-like intermetallic compounds), +3 (arsenates(III) or arsenites, and most organoarsenic compounds), and +5 (arsenates(V): the most stable inorganic arsenic oxycompounds). Arsenic also bonds readily to itself, forming, for instance, As-As pairs in the red sulfide realgar and square As43- ions in the arsenide skutterudite. In the +3 oxidation state, the stereochemistry of arsenic is affected by possession of a lone pair of electrons.

The term "arsenic" was found in the following pages:

Material database: Sigma-Aldrich - Matrix CRM - Soil, Sludge, Sediment: Trace Metals - Sandy Loam 9
Directory of scientists: Jorgelina C. Altamirano de Wuilloud
Elemental speciation is going commercial | EVISA's News
Link database: CBI: Greece legislation: Wood preserved with arsenic and chromium
Link database: FDA: igh Performance Liquid Chromatography-Inductively Coupled Plasma-Mass Spectrometric Determination of Four Arsenic Species in Fruit Juice
LC-ICP-MS: The most often used hyphenated system for speciation analysis | EVISA's News
Arsenic in Pressure-Treated Lumber - Enhancing Childrens Cancer Risks | EVISA's News
Link database: CBI: Austria legislation: Wood preserved with arsenic and chromium
Material database: National Research Council of Canada (NRC - CNRC) - DORM-2
Material database: IRMM - Institute for Reference Materials and Measurements - BCR-422
Directory of scientists: Adrien Mestrot
Material database: Food Analysis Performance Assessment Scheme (FAPAS) - Test Material T07121 (Canned Fish)
Directory of scientists: Christopher F. Harrington
Instrument database: Analytik Jena AG - contrAAź 800 G - Graphite Furnace Atomic Absorption Spectrometer
Material database: IRMM - Institute for Reference Materials and Measurements - ERM- CD281 - Rye Grass
Material database: National Institute of Standards and Technology (NIST) - SRM 83d - Arsenic Trioxide (Reductometric)
Material database: National Analysis Center for Iron & Steel (NACIS) - NCS ZC73013 - Trace Elements in Spinach
Arsenolipids in Fish Oil | EVISA's News
Material database: RECIPE Chemicals + Instruments GmbH - ClinChek 8842 Whole blood, lyophilized, trace elements level III: LOT 445
Material database: FAPAS - Test Material T07121 (Canned Fish)