data_global
_chemical_name_mineral 'Topaz'
loop_
_publ_author_name
'Diego Gatta G'
'Nestola F'
'Bromiley G D'
'Loose A'
_journal_name_full 'American Mineralogist'
_journal_volume 91 
_journal_year 2006
_journal_page_first 1839
_journal_page_last 1846
_publ_section_title
;
 New insight into crystal chemistry of topaz: a multi-methodological study
 Sample: X-ray refinement at T = 298 K
 Note: x(F4) corrected
;
_database_code_amcsd 0004243
_chemical_compound_source 'Ouro Preto, Minas Gerias, Brazil'
_chemical_formula_sum 'Al2 Si O4 F2'
_cell_length_a 4.6601
_cell_length_b 8.8260
_cell_length_c 8.3778
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 344.579
_exptl_crystal_density_diffrn      3.548
_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   0.90530   0.13131   0.08160   1.00000   0.00390
Si   0.39976   0.94088   0.25000   1.00000   0.00330
O1   0.70640   0.03110   0.25000   1.00000   0.00500
O2   0.45160   0.75640   0.25000   1.00000   0.00490
O3   0.21140   0.98979   0.09284   1.00000   0.00470
F4   0.59820   0.25263   0.05988   1.00000   0.00830
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
Al 0.00340 0.00400 0.00436 0.00008 -0.00010 0.00008
Si 0.00270 0.00360 0.00380 0.00010 0.00000 0.00000
O1 0.00410 0.00540 0.00540 0.00170 0.00000 0.00000
O2 0.00590 0.00370 0.00500 0.00090 0.00000 0.00000
O3 0.00460 0.00470 0.00470 0.00070 -0.00110 -0.00030
F4 0.00750 0.00840 0.00890 -0.00230 0.00050 0.00130