rotation-reflection axis

rotation-reflection axis

[rō′tā·shən ri′flek·shən ‚ak·səs] (crystallography) A symmetry element of certain crystals in which a crystal can be brought into a position physically indistinguishable from its original position by a rotation through an angle of 360°/ n about the axis followed by a reflection in the plane perpendicular to the axis, where n is the multiplicity of the axis, equal to 1, 2, 3, 4, or 6.