data_OPT_STEP_8

_cell_length_a           3.90680018
_cell_length_b           3.90680018
_cell_length_c           3.90680018
_cell_angle_alpha       90.00000000
_cell_angle_beta        90.00000000
_cell_angle_gamma       90.00000000

_symmetry_cell_setting                   'cubic'
_symmetry_space_group_name_H-M 'F M 3 M'
_symmetry_Int_Tables_number      225

loop_
_atom_site_type_symbol
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
Mg  MG1     0.00000000    0.00000000    0.00000000
O   O2     -0.50000000   -0.50000000   -0.50000000
