These are different chemical compounds involving copper:

CuO - Copper(II) oxide, a black solid compound used as a pigment and in the production of other copper compounds.CuCl2 - Copper(II) chloride, a greenish-blue solid compound used in the textile industry, as a mordant, and in the production of organic chemicals.Cu(OH)2 - Copper(II) hydroxide, a blue solid compound used in agriculture as a fungicide and in the production of other copper compounds.Cu(NO3)2 - Copper(II) nitrate, a greenish-blue solid compound used in the production of other copper compounds and as a catalyst in organic reactions.Cu3(PO4)2 - Copper(II) phosphate, a green solid compound used in the production of ceramics and as a coloring agent in glasses.