data_global
_chemical_name_mineral 'Beryl'
loop_
_publ_author_name
'Aurisicchio C'
'Fioravanti G'
'Grubessi O'
'Zanazzi P F'
_journal_name_full 'American Mineralogist'
_journal_volume 73 
_journal_year 1988
_journal_page_first 826
_journal_page_last 837
_publ_section_title
;
 Reappraisal of the crystal chemistry of beryl
 Sample: 26
;
_database_code_amcsd 0001180
_chemical_compound_source 'Ural Mountains, Russia'
_chemical_formula_sum 'Si6 Be2.979 Li.018 Al1.925 Fe.018 Mg.06 O18 Na.091'
_cell_length_a 9.2176
_cell_length_b 9.2176
_cell_length_c 9.1968
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 676.711
_exptl_crystal_density_diffrn      2.650
_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   0.38770   0.11610   0.00000   1.00000 ?
Be   0.50000   0.00000   0.25000   0.99300   0.00500
Li   0.50000   0.00000   0.25000   0.00600   0.00500
Al1   0.50000   0.00000   0.25000   0.00100   0.00500
Al2   0.66667   0.33333   0.25000   0.96100 ?
Fe   0.66667   0.33333   0.25000   0.00900 ?
Mg   0.66667   0.33333   0.25000   0.03000 ?
O1   0.30830   0.23490   0.00000   1.00000 ?
O2   0.49830   0.14510   0.14480   1.00000 ?
Na   0.00000   0.00000   0.25000   0.09100 ?
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
Si 0.00460 0.00400 0.00280 0.00240 0.00000 0.00000
Al2 0.00440 0.00440 0.00350 0.00220 0.00000 0.00000
Fe 0.00440 0.00440 0.00350 0.00220 0.00000 0.00000
Mg 0.00440 0.00440 0.00350 0.00220 0.00000 0.00000
O1 0.01170 0.00860 0.01300 0.00810 0.00000 0.00000
O2 0.00820 0.00730 0.00590 0.00420 -0.00280 -0.00070
Na 0.05000 0.05000 0.04950 0.02500 0.00000 0.00000