CoachA centre of inversion is a point through which inversion, , is a symmetry operation.
Examples
Example 4.19 (An achiral molecule without a plane)
Some molecules have neither a mirror plane nor a centre of inversion, yet are achiral because of an axis: the classic case is a spiro compound built from two identically substituted rings at right angles, of point group . Chirality cannot be judged by looking for a plane alone.