Definition:
A parsable string giving one of the symmetry operations of the space group in algebraic form. If W is a matrix representation of the rotational part of the symmetry operation defined by the positions and signs of x, y and z, and w is a column of translations defined by the fractions, an equivalent position X' is generated from a given position X by the equation X' = WX + w (Note: X is used to represent bold_italics_x in International Tables for Crystallography Vol. A, Part 5) When a list of symmetry operations is given, it must contain a complete set of coordinate representatives which generates all the operations of the space group by the addition of all primitive translations of the space group. Such representatives are to be found as the coordinates of the general-equivalent position in International Tables for Crystallography Vol. A (2002), to which it is necessary to add any centring translations shown above the general-equivalent position. That is to say, it is necessary to list explicity all the symmetry operations required to generate all the atoms in the unit cell defined by the setting used.Example:
x,1/2-y,1/2+z | glide reflection through the plane (x,1/4,z), with glide vector 1/2 c |
Type: line
Mandatory item: no
Alias:Related item: _symmetry_equiv.pos_as_xyz (alternate)
Category: space_group_symop
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