kopparIIsalter

koppar(II)salter, or copper(II) salts, are chemical compounds that contain copper in the +2 oxidation state, Cu2+. They form salts with a range of counterions and are widely studied in inorganic chemistry. In aqueous solution the Cu2+ ion forms the hexaaquacopper(II) complex, [Cu(H2O)6]2+, which imparts a characteristic blue color. The salts are typically solid crystalline materials that dissolve to give blue solutions, reflecting the Cu2+ center.

Common copper(II) salts include copper sulfate (CuSO4), copper nitrate (Cu(NO3)2), copper chloride (CuCl2), and copper acetate (Cu(CH3COO)2). Solubility varies: CuSO4 and most nitrates are highly soluble in water; CuCO3 is sparingly soluble and often forms basic salts in air.

Copper(II) salts can be prepared by reacting copper metal or copper(I) compounds with oxidants or acids, for example Cu + 2 HCl → CuCl2 + H2, or by dissolving copper oxide or copper carbonate in an appropriate acid. They may also arise from the dissolution of copper-containing minerals.

In solution the Cu2+ center forms characteristic blue species; adding bases yields blue copper(II) hydroxide, Cu(OH)2, a solid precipitate. With ammonia or amines, copper(II) forms deep blue complex ions such as [Cu(NH3)4]2+. Copper(II) salts participate in redox chemistry, and their reactivity depends on the ligands and environment.

Uses and applications include agricultural fungicides and algaecides (notably copper sulfate), pigments, electroplating, etching, and roles as reagents in qualitative and instrumental analysis. Safety: copper(II) salts are toxic if ingested and can irritate skin and eyes; they pose environmental hazards to aquatic life and should be handled with appropriate precautions.