What kind of copper salt will dissolve in oil?

Copper salts are generally soluble in polar solvents like water but not in nonpolar solvents like oil. However, certain copper salts can form complexes or compounds that might exhibit some solubility in organic solvents under specific conditions. One example of a copper salt that may have some solubility in organic solvents is copper(II) stearate, which is a fatty acid salt of copper. It can dissolve somewhat in nonpolar solvents due to the long hydrocarbon chains of the stearate anions. If you're looking for a copper compound to dissolve in oil, you might explore the formation of surfactants or complexes where the organic component facilitates solubility. Keep in mind that the degree of solubility will depend on factors like temperature, the specific oil used, and the presence of other chemicals.