data_global
_chemical_name_mineral 'Cristobalite'
loop_
_publ_author_name
'Downs R T'
'Palmer D C'
_journal_name_full 'American Mineralogist'
_journal_volume 79 
_journal_year 1994
_journal_page_first 9
_journal_page_last 14
_publ_section_title
;
 The pressure behavior of alpha cristobalite
 P = 0.73 GPa
;
_chemical_formula_sum 'Si O2'
_cell_length_a 4.9028
_cell_length_b 4.9028
_cell_length_c 6.7782
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 162.931
_exptl_crystal_density_diffrn      2.449
_symmetry_space_group_name_H-M 'P 41 21 2'
loop_
_symmetry_equiv_pos_as_xyz
  'x,y,z'
  'y,x,-z'
  '1/2-y,1/2+x,1/4+z'
  '1/2-x,1/2+y,1/4-z'
  '-x,-y,1/2+z'
  '-y,-x,1/2-z'
  '1/2+y,1/2-x,3/4+z'
  '1/2+x,1/2-y,3/4-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_U_iso_or_equiv
Si   0.30860   0.30860   0.00000   0.00798
O   0.23640   0.11980   0.18700   0.01355