Most fundamental reactivity of bicarbonate/carbonato complexes is their interconversion.  This acid-base reaction has been examined mainly for unimolecular complexes. Such reactions are molecular versions of the familiar reaction of acids with carbonate minerals.
Protonation of carbonato complexes gives the corresponding bicarbonate. The structure of bicarbonate complex indicates that protonation occurs at the coordinated oxygen. This process is the microscopic reverse or the first step in the carbonation of metal hydroxides. Protonation of bicarbonate ligands results in loss of carbon dioxide and formation of the metal hydroxide. Particularly well studied are the reactions of  and its ethylenediamine analogue carbonatobis(ethylenediamine)cobalt(III).