Читать книгу Crystallography and Crystal Defects - Anthony Kelly - Страница 20

The fourth symmetry is reflection symmetry. The operation is that of reflection in a mirror. Mirror symmetry relates, for example, our left and right hands. The dotted plane running normal to the paper, marked m in Figure 1.12, reflects object A to A′, and vice versa. A′ cannot be moved about in the plane of the paper and made to superpose on A. The dotted plane is a mirror plane. It should be noted that the operation of inversion through a centre of symmetry also produces a right‐handed object from a left‐handed one.

Figure 1.12 Reflection symmetry