data_global
_chemical_name_mineral 'Quartz'
loop_
_publ_author_name
'Glinnemann J'
'King H E'
'Schulz H'
'Hahn T'
'La Placa S J'
'Dacol F'
_journal_name_full 'Zeitschrift fur Kristallographie'
_journal_volume 198 
_journal_year 1992
_journal_page_first 177
_journal_page_last 212
_publ_section_title
;
 Crystal structures of the low-temperature quartz-type phases of SiO2 and GeO2 at elevated pressure
 P = 4.0 GPa
;
_database_code_amcsd 0011008
_chemical_formula_sum 'Si O2'
_cell_length_a 4.775
_cell_length_b 4.775
_cell_length_c 5.3046
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 104.744
_exptl_crystal_density_diffrn      2.858
_symmetry_space_group_name_H-M 'P 31 2 1'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  'y,x,1/3-z'
  '-y,x-y,1/3+z'
  '-x,-x+y,2/3-z'
  '-x+y,-x,2/3+z'
  'x-y,-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
Si   0.45700   0.00000   0.00000
O   0.40800   0.28810  -0.10330
loop_
_atom_site_aniso_label
_atom_site_aniso_U_11
_atom_site_aniso_U_22
_atom_site_aniso_U_33
_atom_site_aniso_U_12
_atom_site_aniso_U_13
_atom_site_aniso_U_23
Si 0.00120 0.00200 0.00690 0.00100 0.00010 0.00020
O 0.01700 0.00900 0.01100 0.01000 0.00300 0.00100