Special sites with points located on centers of inversion

4 Special sites with points located on centers of inversion 

Fi re 1.45. The distribution of the inversion centers in the triclinic space group symmetry P1. Eight independent centers are labeled from a through h . Inversion centers that are equivalent to one another are marked using symbols of the same size and shading. The invisible centers are drawn using dotted lines. 

there are no positional degrees of freedom available to an atom occupying any special position created by the presence of the center of inversion. Furthermore, unlike in the cases when atoms are located on the mirror planes and rotation or inversion axes, only one atom can occupy any single special position on the center of inversion. 

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