data_global
_chemical_name_mineral 'Topaz'
loop_
_publ_author_name
'Northrup P A'
'Leinenweber K'
'Parise J B'
_journal_name_full 'American Mineralogist'
_journal_volume 79 
_journal_year 1994
_journal_page_first 401
_journal_page_last 404
_publ_section_title
;
 The location of H in the high-pressure synthetic Al2SiO4(OH)2 topaz analogue
 Sample OH synthetic
;
_database_code_amcsd 0001643
_chemical_formula_sum 'Al2 Si O6 H2'
_cell_length_a 4.7203
_cell_length_b 8.9207
_cell_length_c 8.4189
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 354.506
_exptl_crystal_density_diffrn      3.374
_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_occupancy
_atom_site_U_iso_or_equiv
Al   0.90499   0.13210   0.07984   1.00000   0.00418
Si   0.40189   0.94045   0.25000   1.00000   0.00367
O1   0.71040   0.02620   0.25000   1.00000   0.00481
O2   0.44390   0.75610   0.25000   1.00000   0.00456
O3   0.21410   0.99290   0.09430   1.00000   0.00481
O-h   0.59060   0.25070   0.06590   1.00000   0.00659
H1   0.44300   0.19900   0.08800   0.50000   0.03420
H2   0.60700   0.28100   0.15100   0.50000   0.08992