data_global
_chemical_name_mineral 'Tridymite'
loop_
_publ_author_name
'Dollase W A'
_journal_name_full 'Acta Crystallographica'
_journal_volume 23 
_journal_year 1967
_journal_page_first 617
_journal_page_last 623
_publ_section_title
;
 The crystal structure at 220 C of orthothombic high tridymite
 from the Steinbach meteorite
 Note: T = 220 C
;
_database_code_amcsd 0020733
_chemical_compound_source 'Steinbach meteorite'
_chemical_formula_sum 'Si O2'
_cell_length_a 8.74
_cell_length_b 5.04
_cell_length_c 8.24
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 362.969
_exptl_crystal_density_diffrn      2.199
_symmetry_space_group_name_H-M 'C 2 2 21'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '1/2+x,1/2+y,z'
  '-x,y,-z'
  '1/2-x,1/2+y,-z'
  'x,-y,1/2-z'
  '1/2+x,1/2-y,1/2-z'
  '-x,-y,1/2+z'
  '1/2-x,1/2-y,1/2+z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
Si   0.16846   0.53589   0.43857
O1   0.33360   0.00000   0.75000
O2   0.00000   0.55970   0.50000
O3   0.25470   0.30290   0.52130
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 0.04605 0.03346 0.04093 0.00268 -0.00036 -0.00274
O1 0.15479 0.10295 0.05848 0.00000 0.00000 0.01894
O2 0.04644 0.17501 0.10319 0.00000 0.00730 0.00000
O3 0.15866 0.06949 0.08599 0.05356 -0.02189 0.01683