MTSD@UPC 第一节晶体结构 七个晶系 Table 18A.1 The seven crystal systems System Essential symmetries Triclinic None Monoclinic One C2 axis Orthorhombic Three perpendicular C2 axes Rhombohedral One Ca axis Tetragonal One Ca axis Hexagonal One C axis Cubic Four C3 axes in a tetrahedral arrangement 2022/3/24 材料化学系：结构化学 10 MTSD@UPC 2022/3/24 材料化学系：结构化学 10 第一节 晶体结构 七个晶系