data_9007423
_chemical_name '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
 Locality: Ouro Preto, Minas Gerias, Brazil
 Sample: P = 8.39 GPa
;
_chemical_formula_sum 'Al2 Si O4 F2'
_cell_length_a 4.5841
_cell_length_b 8.7308
_cell_length_c 8.2316
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 329.452
_symmetry_space_group_name_H-M 'P b n m'
loop_
_symmetry_equiv_pos_as_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_Uiso_or_equiv
Al   0.90690   0.13130   0.08070   0.00410
Si   0.40160   0.94130   0.25000   0.00410
O1   0.78820   0.52760   0.25000   0.00370
O2   0.44900   0.75460   0.25000   0.00370
O3   0.78450   0.00860   0.90940   0.00370
FO   0.90750   0.75310   0.06530   0.01120