Order n of an axis can be regarded as a number of times that, for the least rotation which gives an equivalent configuration, that rotation must be repeated to give a configuration identical to the original structure (i.e. a 360° or 2 π rotation). An example of this is C 3 proper rotation, which rotates by ⁠ 2 π π 3 . ⁠ C 3 represents the first rotation around the C 3 axis by ⁠ 2 π π 3 , ⁠ ⁠ C 3 2 ⁠ is the rotation by ⁠ 2 × × 2 π π 3 , ⁠ while ⁠ C 3 3 ⁠ is the rotation by ⁠ 3 × × 2 π π 3 . ⁠ ⁠ C 3 3 ⁠ is the identical configuration because it gives the original structure, and it is called an identity element (E). Therefore, C 3 is an order of three, and is often referred to as a threefold axis.