Symmetry Operation + R/ J9 L( @; s: u# V% b
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. ; x; Q2 `! A- A
The Inversion Operation takes / U! G$ P* X1 R* b/ G
(x,y,z)=>(-x,-y,-z); {$ a- p" s& z2 k! ?$ ?6 I
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. 2 R% d- @6 ?+ `1 X; s% m
The Mirror Plane symmetry operation takes - {: z2 H5 ^ N! i9 t( o! q5 G
(x,y,z)=>(x,y,-z)=>(x,-y,z) , S) }, a) j# n- I4 Fetc., which is equivalent to 2.