data_global
_chemical_name_mineral 'Cristobalite'
loop_
_publ_author_name
'Le Bail A'
_journal_name_full 'Journal of Non-Crystalline Solids'
_journal_volume 183 
_journal_year 1995
_journal_page_first 39
_journal_page_last 42
_publ_section_title
;
 Modelling the silica glass structure by the Rietveld method
 Note: model for amorphous silica based on cristobalite-type topology
;
_database_code_amcsd 0020708
_chemical_formula_sum 'Si O2'
_cell_length_a 7.22
_cell_length_b 7.09
_cell_length_c 7.30
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 373.686
_exptl_crystal_density_diffrn      2.136
_symmetry_space_group_name_H-M 'P 21 21 21'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '-x,1/2+y,1/2-z'
  '1/2+x,1/2-y,-z'
  '1/2-x,-y,1/2+z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
Si1   0.27700   0.27500   0.28200
Si2   0.00900   0.02200   0.01600
O1   0.12500   0.14900   0.15200
O2   0.63500   0.65700   0.06100
O3   0.06500   0.64600   0.65400
O4   0.67000   0.06000   0.62100