Formation of star-shaped calcite crystals with Mg2+ inorganic mineralizer without organic template

Star-shaped calcite crystals with image symmetry were obtained in the mixed solvent of ethanol and H2O (4:1 vol%) using Mg2+ as grow mineralizer without any organic template under the solvothermal condition. The crystals branched to the six directions perpendicular to the c-axis. In the process, Mg2+ takes an important influence on such novel morphology via entering the crystal lattice of calcite to absorb the special plane and change the general growth habit. The aqueous solvent is favorable to form aragonite, while the presence of alcohol promotes the formation of calcite, the thermodynamically stable phase. The products were characterized by the techniques of XRD, SEM, SAED, IR and ICP. The formation process was also primarily studied.