The crystalline chloride form of layered double hydroxide (LDH) with the formula Mg0.75Al0.25(OH)(2)Cl-0.25 center dot mH(2)O was gradually exchanged with F-, Br-, or I- up to a total displacement of Cl-. For the A three anions, both the exchange isotherms as well as the structural changes were inspected along the whole range of chloride displacement. The bulkier Br- and I- followed an ideal exchange behavior isotherm while F- denoted strong deviations from the ideal regime as well as phase segregation. The exchange constants recorded herein were contrasted with bibliographic data belonging to an analogous LDH host, revealing a strong linear free energy correlation. Higher Al(III) to Mg(II) ratios, or layer charge densities, favor a stronger selectivity for smaller halides. For both hosts, the exchange free energy was satisfactorily described in terms of strictly electrostatic-based models.