Symmetry Operation . Q. N+ a; y4 n$ w9 j* M$ f1 K& |
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. ! u0 f% U b3 \3 F. ?1 J, ` `2 t% nThe Inversion Operation takes ( Z2 Q) o: ~' O( s2 X, N(x,y,z)=>(-x,-y,-z)) R# H2 O/ \, e. `" B
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. 7 h) y% w: c; D. }: K
The Mirror Plane symmetry operation takes % y0 F9 B8 |; H' I/ a
(x,y,z)=>(x,y,-z)=>(x,-y,z) ) |" \1 b! @1 G" @etc., which is equivalent to 2.