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 = 573 K
;
_database_code_amcsd 0020933
_chemical_compound_source 'synthetic refractory silica brick'
_chemical_formula_sum 'Si O2'
_cell_length_a 8.764
_cell_length_b 5.039
_cell_length_c 8.235
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 363.672
_exptl_crystal_density_diffrn      2.195
_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   0.16820   0.53520   0.43800
O1   0.32730   0.00000   0.75000
O2   0.00000   0.55720   0.50000
O3   0.25330   0.30300   0.52160
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 0.04319 0.03872 0.03745 0.00291 0.00110 -0.00252
O1 0.11557 0.12400 0.04020 0.00000 0.00000 0.01661
O2 0.04514 0.19244 0.12231 0.00000 -0.00146 0.00000
O3 0.14164 0.07602 0.10719 0.04654 -0.01499 0.02144