When outputting a CIF from GULP, the formatting doesn’t seem to be perfect in terms of the expected spec for a CIF. Some of the CIF parsing programs I use (e.g. ASE) only work correctly if I modify the CIF slightly. Namely, there are two loop_
lines. My understanding is that loop_
should only be used for tables, so things like x,y,z coordinates, but I certainly could be wrong. There’s some additional discussion here.
data_cif
_audit_creation_method 'generated by GULP'
_symmetry_space_group_name_H-M '(unknown) '
_symmetry_Int_Tables_number 1
loop_
_symmetry_equiv_pos_site_id
_symmetry_equiv_pos_as_xyz
_cell_length_a 5.1053
_cell_length_b 5.1053
_cell_length_c 5.1053
_cell_angle_alpha 60.0000
_cell_angle_beta 60.0000
_cell_angle_gamma 60.0000
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
Cu 0.00000 0.00000 0.00000 1.0000
Cu 0.00000 0.00000 0.50000 1.0000
Cu 0.00000 0.50000 0.00000 1.0000
Cu 1.00000 0.50000 0.50000 1.0000
Cu 0.50000 0.00000 0.00000 1.0000
Cu 0.50000 1.00000 0.50000 1.0000
Cu 0.50000 0.50000 0.00000 1.0000
Cu 0.50000 0.50000 0.50000 1.0000