Centrosymmetry

In crystallography, a centrosymmetric point group contains an inversion center as one of its symmetry elements.

[3] Point groups lacking an inversion center (non-centrosymmetric) can be polar, chiral, both, or neither.

One or more unique polar axes could be made through two such collinear unmoved points.

No inversion, reflection, roto-inversion or roto-reflection (i.e., improper rotation) symmetry exists in such point group.

The remaining non-centrosymmetric crystallographic point groups 4, 42m, 6, 6m2, 43m are neither polar nor chiral.