TetramminecobaltIII

Tetramminecobalt(III) refers to a coordination complex featuring a cobalt ion in the +3 oxidation state, coordinated to four ammonia ligands. The chemical formula is typically represented as [Co(NH₃)₄X₂]ⁿ⁺, where X represents another ligand, often a halide or other anion, and n is the charge of the complex. The tetraamminecobalt(III) cation is a common species. These complexes are generally diamagnetic due to the low-spin d⁶ configuration of cobalt(III). The geometry around the cobalt ion is octahedral.

Tetramminecobalt(III) complexes are often synthesized through the amination of cobalt(II) precursors followed by oxidation to the cobalt(III) state. For example, the synthesis of chlorotetramminecobalt(III) chloride can involve reacting cobalt(II) chloride with ammonia and ammonium chloride, followed by oxidation with an agent like hydrogen peroxide. The resulting complexes are typically crystalline solids and can exhibit various colors depending on the specific counterions and auxiliary ligands. They have found applications in inorganic chemistry research, particularly in studying ligand substitution reactions and redox properties of cobalt complexes. Their stability is a characteristic feature, with cobalt(III) complexes generally being kinetically inert.