Arsenic is the third member of the nitrogen family, which consists of elements in Group 15 of the periodic table. Its atomic number is 33, its atomic mass is 74.9216, and its chemical symbol is As.

Properties

Arsenic occurs in two allotropic forms, the more common of which is a shiny, gray, brittle, metallic-looking solid. The less common allotrope is a yellow crystalline solid produced when vapors of arsenic are cooled suddenly. When heated, arsenic does not melt, as do most solids. Instead, it sublimes. However, under high pressure, arsenic can be forced to melt at a temperature of about 1,500°F (814°C). Arsenic's density is 5.72 grams per cubic centimeter.

Chemically, arsenic is a metalloid. When heated in air, it reacts with oxygen to form arsenic oxide (As₂O₃). The reaction results in the formation of a characteristic blue flame and a distinctive garlic-like odor.

Occurrence and Extraction

Arsenic is...