Symmetry Operation / i) f Y( f jSymmetry operations include the Improper Rotation, Inversion Operation, Mirror Plane, and Rotation. Together, these operations create 32 crystal classes corresponding to the 32 Point Groups. 8 |2 ?% w$ b7 C; \ P% T
The Inversion Operation takes ! J! o+ X% L" M5 b9 F; |(x,y,z)=>(-x,-y,-z) # L3 P: H' d# G( r1 ~! J8 ` 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. * p$ J3 h7 V( w) {6 P1 \
The Mirror Plane symmetry operation takes 4 q! Q" V4 Z0 Q: `* C) |8 |(x,y,z)=>(x,y,-z)=>(x,-y,z)* c& Q: ?7 n2 h; F8 _; ~
etc., which is equivalent to 2.