There are two series of copper compounds, the cupric and the cuprous. Cupric compounds are most common.
The most important copper compound is cupric sulfate, more commonly called copper sulfate or blue vitriol. It is used in making fungicides, in electroplating, and in the manufacture of other copper compounds.
Cupric oxide (black oxide of copper) is found in the ores called melaconite and tenorite. The compound is used as an oxidizing agent and to rectify (change) alternating current to direct current. Cuprous oxide (red oxide of copper) is found in a crystallized form in several copper ores.
Cupric arsenite, or Scheele's green, is used in paint pigments and as an insecticide. Paris green (cupric acetoarsenite) is a useful insecticide and wood preservative. Cupric acetate has a similar use, and is also a textile dye.