Abstract: Based on the theoretical model of anionic coordination po1yhedron growth units,this paper discussed the relationship between the crystal morphology and the orientation of anionic coordination polyhedra in the isomer (rutile,brookite and anatase)and allomer (rutile and cassiterite;corundum,hematite and ilmenite). It was found that the crystal habits of these crystals were related to the stability of combination of anionic coordination polyhedron growth units with different faces.The combination of the vertexes is the best stable,the edge second and the face third.Furthermore,the morphology of polar crystals ZnS and ZnO was also interpreted in the viewpoint of anionic coordination polyhedron growth units.

Key words: Based on the theoretical model of anionic coordination po1yhedron growth units,this paper discussed the relationship between the crystal morphology and the orientation of anionic coordination polyhedra in the isomer (rutile,brookite and anatase)and allomer (rutile and cassiterite;corundum,hematite and ilmenite). It was found that the crystal habits of these crystals were related to the stability of combination of anionic coordination polyhedron growth units with different faces.The combination of the vertexes is the best stable,the edge second and the face third.Furthermore,the morphology of polar crystals ZnS and ZnO was also interpreted in the viewpoint of anionic coordination polyhedron growth units.