HexakisacetatocobaltIII

Hexakisacetatocobalt(III) refers to the coordination compound in which a cobalt(III) ion is surrounded by six acetate ligands, giving the hexakis(acetato)cobaltate(III) anion [Co(OAc)6]3−. This anion is most commonly encountered as salts with alkali metal cations, such as Na3[Co(OAc)6] or K3[Co(OAc)6], and is generally prepared in aqueous solution or by metathesis reactions from cobalt(III) acetate sources.

Structure and bonding at cobalt(III) are typically described as octahedral coordination, with six acetato ligands coordinating to the metal center. In this context, acetate ligands can bind in various modes, but in the hexakisacetato complex they are commonly treated as coordinating through a single oxygen atom to achieve six-coordinate saturation. Cobalt(III) in this complex is in a low-spin d6 configuration, which often leads to diamagnetic behavior.

Synthesis methods commonly involve oxidation of cobalt(II) acetate in acetate-containing media to form the [Co(OAc)6]3− anion, followed by pairing with suitable alkali metal cations to yield stable salts. Alternatively, salt metathesis from preformed cobalt(III) acetate derivatives in the presence of excess acetate can furnish hexakisacetato cobaltate(III) salts.

Applications of hexakisacetatocobalt(III) are primarily within inorganic synthesis and coordination chemistry, where the complex serves as a source of Co(III) with aerially defined acetate ligands or as a study medium for ligand exchange and coordination behavior in six-coordinate cobalt(III) systems. The complex is typically handled under aqueous or mildly basic conditions, and its stability is enhanced by the chelating effect of the acetate framework in the solid salts.