data_global
_chemical_name_mineral 'Tridymite'
loop_
_publ_author_name
'Kihara K'
'Matsumoto T'
'Imamura M'
_journal_name_full 'Zeitschrift fur Kristallographie'
_journal_volume 177 
_journal_year 1986
_journal_page_first 27
_journal_page_last 38
_publ_section_title
;
 Structural change of orthorhombic-I tridymite with temperature:
 A study based on second-order thermal-vibrational parameters
 Note: Dollase's model, T = 693 K
;
_database_code_amcsd 0020935
_chemical_compound_source 'synthetic refractory silica brick'
_chemical_formula_sum 'Si O2'
_cell_length_a 8.742
_cell_length_b 5.047
_cell_length_c 8.262
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 364.527
_exptl_crystal_density_diffrn      2.190
_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   0.16730   0.50990   0.43780
O1   0.32750   0.00000   0.75000
O2   0.00000   0.52520   0.50000
O3   0.24870   0.26550   0.50490
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 0.04685 0.04400 0.04081 -0.00067 -0.00220 -0.00380
O1 1.33183 0.13201 0.04530 0.00000 0.00000 0.01436
O2 0.04917 0.21925 0.12622 0.00000 0.03000 0.00000
O3 0.15486 0.09833 0.13314 0.05879 -0.02525 0.02788