Symmetry Operation ! V$ x4 a: [/ t& C. E( ]
Symmetry operations include the Improper Rotation, Inversion Operation, Mirror Plane, and Rotation. Together, these operations create 32 crystal classes corresponding to the 32 Point Groups. 6 ^! Z, @: `0 Q9 G0 Q0 F% j% l- ?6 AThe Inversion Operation takes $ X* j% R% e4 g" q3 t4 R. h(x,y,z)=>(-x,-y,-z)* Y; o s2 X+ [& @8 g$ {/ G7 @
and is denoted i. When used in conjunction with a Rotation, it becomes an Improper Rotation. An Improper Rotation by 360/n . For periodic crystals, the Crystallography Restriction allows only the Improper Rotations 1, 2, 3, 4, and 6. . |" O3 v3 b7 H+ g- IThe Mirror Plane symmetry operation takes + E4 B( g* I9 g
(x,y,z)=>(x,y,-z)=>(x,-y,z)* k: |) O- L* x7 c0 [; U
etc., which is equivalent to 2.