It is found in group Ib of the periodic table , together with silver and gold. Copper has low chemical reactivity. Salt water corrodes copper, forming a chloride. Compounds The most important chemical compound of copper is copper sulfate pentahydrate, also called bluestone or blue vitriol. Other compounds include Paris green , Bordeaux mixture , a cyanide, a chloride, oxides, and a basic carbonate.
Verdigris is basic copper acetate.
Sources and Ores Small amounts of copper are found uncombined, particularly near Lake Superior in Michigan. Copper ores are found in various parts of the world. The principal ore of copper is chalcopyrite , a sulfide of copper and iron, also called copper pyrite. Azurite is a blue crystalline basic carbonate of copper found with other copper ores. Chrysocolla is a bluish-green copper silicate ore.