data_global
_chemical_name_mineral 'Beryl'
loop_
_publ_author_name
'Artioli G'
'Rinaldi R'
'Stahl K'
'Zanazzi P F'
_journal_name_full 'American Mineralogist'
_journal_volume 78 
_journal_year 1993
_journal_page_first 762
_journal_page_last 768
_publ_section_title
;
 Structure refinements of beryl by single-crystal neutron and X-ray diffraction
 Sample no. 2, aquamarine, probed with neutrons, T = 295 K
;
_database_code_amcsd 0001605
_chemical_formula_sum 'Si6 Be3 (Al1.97 Fe.03) O18.24 Na.016 H.26'
_cell_length_a 9.218
_cell_length_b 9.218
_cell_length_c 9.197
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 676.784
_exptl_crystal_density_diffrn      2.664
_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
_atom_site_occupancy
_atom_site_U_iso_or_equiv
Si   0.38720   0.11570   0.00000   1.00000   0.00291
Be   0.50000   0.00000   0.25000   1.00000   0.00570
Al   0.66667   0.33333   0.25000   0.98500   0.00342
Fe   0.66667   0.33333   0.25000   0.01500   0.00342
O1   0.30980   0.23630   0.00000   1.00000   0.00874
O2   0.49866   0.14541   0.14517   1.00000   0.00583
Na   0.00000   0.00000   0.25000   0.01600   0.06333
OW   0.00000   0.00000   0.25000   0.24000   0.06333
H   0.00000   0.00000   0.16500   0.13000   0.05066