Concerning the existence of perchloratopentamminecobalt(III) perchlorate

Contrary to earlier reports, treatment of aqueous chloropentamminecobalt(III) ion with silver oxide and then with perchloric acid yields aquopentamminecobalt(III) perchlorate, and not perchloratopentamminecobalt(III) perchlorate. No detectable inner-sphere substitution of perchlorate for water in aquopentamminecobalt(III) ion takes place in aqueous perchloric acid of up to at least 5 M concentration at 25°. Solid aquopentamminecobalt(III) perchlorate is stable at 110°, but heating above 160° results in slow general decomposition to Co3O4 without the intermediate formation of perchloratopentamminecobalt(III) perchlorate; the solid explodes violently at 290°.