Arsenic

**Semantic type:** Element, Ion, or Isotope|Hazardous or Poisonous Substance

**Definition:** A naturally occurring allotropic pnictogen and metalloid trace element with atomic symbol As, atomic number 33, and atomic weight 74.92 that is found in water, air, food, and soil, and has a role as a micronutrient. Arsenic, which is highly toxic with acute or chronic exposure to moderate or high levels through an unknown mechanism of action, is used in many industrial processes, as well as in pharmaceuticals, feed additives, and pesticides. It is characterized as a white, yellow, gray metallic, or black solid that is odorless. Exposure occurs by inhalation, ingestion, or contact.

**Synonyms:** - ARSENIC - ARSENIC - As - arsenic