rotoinversion

The symmetry operation corresponding to a rotation followed by an inversion operation, also called a rotoinversion. This operation is denoted n^_ for an improper rotation by 360°/n, so the crystallography restriction gives only 1^_, 2^_, 3^_, 4^_, 6^_ for crystals. The mirror plane symmetry operation is (x, y, z)->(x, y, - z), etc., which is equivalent to 2^_.

inversion operation | rotation | symmetry operation