Anionic clay compounds such as hydrotalcite-like compounds can be made by a process wherein a non-hydrotalcite-like compound (or a hydrotalcite-like compound) are heat treated and then hydrated to form hydrotalcite-like compounds having properties (e.g., increased hardness and/or density) that differ from those of hydrotalcite-like compounds made by prior art methods wherein non-hydrotalcite-like compounds (or hydrotalcite-like compounds) are not similarly heat treated and hydrated to form such hydrotalcite-like compounds.