data_global
_chemical_name_mineral 'Beryl'
loop_
_publ_author_name
'Bragg W'
_journal_name_full 'Proceedings of the Royal Society of London'
_journal_volume A111 
_journal_year 1926
_journal_page_first 691
_journal_page_last 714
_publ_section_title
;
 The structure of beryl, Be3Al2Si6O18
 _cod_database_code 1010541
;
_database_code_amcsd 0017446
_chemical_formula_sum 'Al2 Be3 Si12 O24'
_cell_length_a 9.21
_cell_length_b 9.21
_cell_length_c 9.17
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 673.627
_exptl_crystal_density_diffrn      3.954
_symmetry_space_group_name_H-M 'P 6/m c c'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '-x,-x+y,1/2+z'
  'x,x-y,1/2-z'
  '-x+y,-x,-z'
  'x-y,x,z'
  '-y,-x,1/2+z'
  'y,x,1/2-z'
  'y,-x+y,-z'
  '-y,x-y,z'
  'x-y,-y,1/2+z'
  '-x+y,y,1/2-z'
  'x,y,-z'
  '-x,-y,z'
  'x,x-y,1/2+z'
  '-x,-x+y,1/2-z'
  'x-y,x,-z'
  '-x+y,-x,z'
  'y,x,1/2+z'
  '-y,-x,1/2-z'
  '-y,x-y,-z'
  'y,-x+y,z'
  '-x+y,y,1/2+z'
  'x-y,-y,1/2-z'
  '-x,-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
Al   0.66667   0.33333   0.00000
Be   0.50000   0.00000   0.00000
Si   0.39000   0.12000   0.25000
O1   0.48000   0.15000   0.10000
O2   0.30000   0.24000   0.25000