copperarsenate

Copper arsenate is a term used for inorganic compounds containing copper(II) and arsenate (AsO4^3−) groups. The name most often refers to a family of basic copper arsenates, in which copper(II) is coordinated with arsenate linkages and hydroxide or water can be present in the structure.

Common formulations include Cu3(AsO4)2(OH)3 and Cu2(AsO4)(OH)2, with varying hydration. In nature, copper arsenate compounds occur as minerals; olivenite, Cu2(AsO4)(OH)2, is the best-known example.

Preparation and occurrence: In the laboratory, basic copper arsenates can be prepared by reacting copper salts (for example copper sulfate) with arsenate sources under basic conditions, followed by crystallization and, if desired, hydration. In nature, they form through weathering and oxidation of copper-bearing minerals in arsenic-rich environments.

Properties: These compounds are typically green to greenish-blue and generally have low solubility in water. They are relatively stable under ambient conditions but can decompose upon heating and in strongly acidic or strongly reducing environments.

Uses and significance: Historically, related copper arsenate compounds have attracted interest as pigments and in inorganic chemistry, though toxicity concerns limit practical applications today. They are studied for their crystal chemistry and copper-arsenate bonding.

Safety: Arsenic-containing compounds are toxic and can be hazardous if ingested, inhaled, or absorbed; appropriate safety measures are required when handling.