**
Sixfold Screw Axes (6**_{n})
Return link to the symbol table

The symbols above show sixfold screw axes perpendicular to the
plane of the screen, i.e parallel to Z.
A sixfold screw axis is equivalent to an anticlockwise rotation of 60°
about a line followed by a translation parallel to that line.
The translation is either 1/6, 1/3, 1/2, 2/3, or 5/6 of the repeat distance
in the lattice along the axis for six-one, six-two, six-three, six-four, and
six-five screw axes, respectively.
A six-one screw axis with
a sixfold rotation about the *c*-axis, i.e. about
the line 0,0,*z*, followed by a translation of 1/6 *c*
along it, will have
the corresponding symmetry operator *x*-*y*,*x*,1/6+*z*.
Note that six-one and six-five are equivalent
except for handedness (right- and left-handed, respectively) as
are six-two and six-four screw axes,
in contrast to the six-three axis, which has no handedness.

These axes have the written symbols "6_{1}",
"6_{2}",
"6_{3}",
"6_{4}", and
"6_{5}", respectively.

© Copyright 1997-1999.
Birkbeck College, University of London.