Minerals with the general formula Cu4(OH)6A2/nn ± pH2O (A = Cl–, NO3–, SO42–) were synthesized and their behaviour
following treatment with chloride, nitrate and sulfate solutions was studied by powder XRD and SEM. Two types of transformation were found: (1) an ion-exchange reaction manifested by preservation of both the precursor's morphology and structural type; (2) a dissolution-crystallization mechanism
characterized by changes in the structural type and the morphology. The results were considered by simultaneous application of the binary presentation of the structures, a bond valence approach and the ion-exchange ability. It was found that the structures of minerals with ion-exchange
properties are built from similar layered structural unit of edge-shared and corner-shared Jahn-Teller square frameworks and different interstitial complexes of exchangeable ions, water molecules and cation-water groups. On the basis of their structural features the position of the investigated
minerals in mineralogical classifications is also discussed.