When connecting a copper ground wire to a copper-plated ground rod, is
there a compound of some kind that should be used to inhibit
corrosion?


The best way to connect copper grounding connections is with CadWeld.

However, I find the best non-weld solution is a liberal use of a
product called " Kopr-Shield " on the copper clamps. Its pricey, but
better than any of those so called conductive grease compounds. Do a
Google search to find it.


Ed K7AAT