CoSO₄Cl·5NH₃ exists in two isomeric forms, 'A' and 'B', which differ in their chemical and physical properties, primarily due to the different arrangements of ligands around the central cobalt ion. In isomer 'A', the ammonia molecules (NH₃) and the chloride ion (Cl⁻) are arranged in such a way that AgNO₃ (silver nitrate) reacts with isomer 'A', resulting in the formation of a white precipitate. This occurs due to the formation of silver chloride (AgCl) when the chloride ion from the complex reacts with AgNO₃. However, isomer 'A' does not react with BaCl₂ (barium chloride), indicating that the arrangement of ligands in this isomer does not allow for the formation of a precipitate with BaCl₂.

In contrast, isomer 'B' has a different ligand arrangement, which causes it to react with BaCl₂.