# Symmetry operation

A **symmetry operation** is an **isometry**, *i*.*e*. a transformation under which two objects, or two configurations or an object, are brought to

The two configurations/objects can be either congruent or enantiomorphous. Correspondingly, the symmetry operations are classed into two kinds:

**symmetry operations of first kind**: they relate congruent objects and consist of translations, rotations and screw rotations;**symmetry operations of second kind**: they relate enantiomorphous objects and consist of inversion, reflections, rotoinversions, and glide reflections. There exist a 1:1 correspondence between rotoinversion and rotoreflections: the latter are more used in Schoenflies notation, whereas rotoinversions are preferred in Hermann-Mauguin notation.

A symmetry operation is performed about a symmetry element.