**Symmetry Elements and Symmetry Operations**

What do we mean by symmetry in chemistry? When we say that a molecule has *symmetry *, we mean that certain parts of it can be interchanged with others without altering either the identity or the orientation of the molecule. Interchangeable parts are said to be equivalent to one another by symmetry.

A symmetry element is a geometrical entity about which a symmetry operation is performed. A symmetry element can be a point, axis, or plane. A symmetry operation is the movement of a body (molecule) such that after the movement the molecule appears the same as before. The existence of a symmetry operation implies the existence of a corresponding symmetry element, and conversely, the presence of a symmetry element means that a certain symmetry operation or set of operations is possible.

There are five basic kinds of symmetry operations

Examples of each of these symmetry operations now follow. You can explore these operations in your own time by going to the following website.

Next: Rotations

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