Is odium chloride a compound?

Yes

yes chloride is a compound. single atom of chlorine is not stable. so easily combines with another chlorine atom and forms a molecule and which is also unstable so it readily binds with other...

No, it is ionic as are all sodium compounds.

Copper(II) chloride is already a compound; its formula is CuCl2

Yes. It has constant proportions between lithium and chlorine but can be decomposed into its elements.