Hydrotalcite and hydrocalumite are two close minerals belonging to the layered double hydroxide family. Both structures are based on positive brucite-like layers alternating with layers containing anions and water molecules. Most of synthetic ðLDHsÞ are hydrotalcite-like materials. On the other hand, the hydrocalumite structure type is rare for those less broad in composition, typically Ca 2þ and Al 3þ in the hydroxide layers. In order to get further insight into the conditions of stabilization of this structure type, we have undertaken the synthesis and the structural characterization by powder X-ray diffraction of the series Ca 2 M 3þ ðOHÞ 6 Cl . 2H 2 OðM 3þ : Al 3þ ; Ga 3þ ; Fe 3þ and Sc 3þ ). The incorporation of Sc 3þ ions is quite original. All phases crystallize in the rhombohedral space group R-3 resulting in a three-layers polytype. The main consequence of the replacement of Al 3þ cations by large M 3þ cations is a compression of the octahedral layers like it proceeds in hydrotalcite-like materials. The existence of Sc-containing phase allows us to say that it is the size of Ca 2þ ions and the pronounced anisotropy of coordination spheres around Ca 2þ and M 3þ which are responsible for the ordered distribution of cations in hydrocalumite-like materials.