Tables for
Volume A
Space-group symmetry
Edited by M. I. Aroyo

International Tables for Crystallography (2016). Vol. A, ch. 2.1, p. 149


Th. Hahna and M. I. Aroyoc

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Graphical symbols of symmetry axes inclined to the plane of projection (in cubic space groups only)

DescriptionGraphical symbolScrew vector of the defining operation of the screw axis (in units of the shortest lattice translation vector parallel to the axis)Symmetry elements represented by the graphical symbol
Twofold rotation axis [Scheme scheme71] [Scheme scheme77] None 2
Twofold screw axis: `2 sub 1' [Scheme scheme72] [{1 \over 2}] [2_{1}]
Threefold rotation axis [Scheme scheme73] [Scheme scheme78] None 3
Threefold screw axis: `3 sub 1' [Scheme scheme74] [{1 \over 3}] [3_{1}]
Threefold screw axis: `3 sub 2' [Scheme scheme75] [{2 \over 3}] [3_{2}]
Inversion axis: `3 bar' [Scheme scheme76] None [\bar{3}, 3,\bar{1}]
The dots mark the intersection points of axes with the plane at [h = 0]. In some cases, the intersection points are obscured by symbols of symmetry elements with height [h \geq 0]; examples: [Fd\bar{3}] (203), origin choice 2; [Pn\bar{3}n] (222), origin choice 2; [Pm\bar{3}n] (223); [Im\bar{3}m] (229); [Ia\bar{3}d] (230).