data_global
_chemical_name_mineral 'Topaz'
loop_
_publ_author_name
'Gatta G D'
'Nestola F'
'Ballaran T B'
_journal_name_full 'Physics and Chemistry of Minerals'
_journal_volume 33 
_journal_year 2006
_journal_page_first 235
_journal_page_last 242
_publ_section_title
;
 Elastic behaviour and structural evolution
 of topaz at high pressure
 Sample: P = 3.14 GPa
;
_database_code_amcsd 0009027
_chemical_compound_source 'Ouro Preto, Minas Gerias, Brazil'
_chemical_formula_sum 'Al2 Si O4 F2'
_cell_length_a 4.6325
_cell_length_b 8.7938
_cell_length_c 8.3254
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 339.154
_exptl_crystal_density_diffrn      3.604
_symmetry_space_group_name_H-M 'P b n m'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  'x,y,1/2-z'
  '-x,-y,1/2+z'
  '1/2+x,1/2-y,1/2+z'
  '1/2-x,1/2+y,1/2-z'
  '1/2-x,1/2+y,z'
  '1/2+x,1/2-y,-z'
  '-x,-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_U_iso_or_equiv
Al   0.90470   0.13070   0.08160   0.00530
Si   0.40090   0.94070   0.25000   0.00410
O1   0.79190   0.52950   0.25000   0.00440
O2   0.44710   0.75470   0.25000   0.00570
O3   0.78760   0.01010   0.90800   0.00530
FO   0.90210   0.75290   0.06250   0.01290