Copper is a reddish-brown, ductile and malleable metal. It belongs to group IB of the Periodic Table. In compounds found in the environment it usually has a valence of 2 but can exist in the metallic, +1 and +3 valence states. Copper is found naturally in a wide variety of mineral salts and organic compounds, and in the metallic form. The metal is sparingly soluble in water, salt or mildly acidic solutions, but can be dissolved in nitric and sulfuric acids as well as basic solutions of ammonium hydroxide or carbonate. Copper possesses high electrical and thermal conductivity and resists corrosion.