Data items in the GEOM_TORSION category record details about
torsion angles as calculated from the
contents of the ATOM, CELL and SYMMETRY data.
The vector direction _geom_torsion.atom_site_id_2 to
_geom_torsion.atom_site_id_3 is the viewing direction, and the
torsion angle is the angle of twist required to superimpose the
projection of the vector between site 2 and site 1 onto the
projection of the vector between site 3 and site 4. Clockwise
torsions are positive, anticlockwise torsions are negative.
Ref: Klyne, W. & Prelog, V. (1960). Experientia, 16, 521-523.
loop_
_geom_torsion.atom_site_id_1
_geom_torsion.atom_site_id_2
_geom_torsion.atom_site_id_3
_geom_torsion.atom_site_id_4
_geom_torsion.value
_geom_torsion.site_symmetry_1
_geom_torsion.site_symmetry_2
_geom_torsion.site_symmetry_3
_geom_torsion.site_symmetry_4
_geom_torsion.publ_flag
C(9) O(2) C(7) C(2) 71.8 . . . . yes
C(7) O(2) C(9) C(10) -168.0 . . . 2_666 yes
C(10) O(3) C(8) C(6) -167.7 . . . . yes
C(8) O(3) C(10) C(9) -69.7 . . . 2_666 yes
O(1) C(1) C(2) C(3) -179.5 . . . . no
O(1) C(1) C(2) C(7) -0.6 . . . . no