data_global
_chemical_name_mineral 'Beryl'
loop_
_publ_author_name
'Sherriff B L'
'Grundy H D'
'Hartman J S'
'Hawthorne F C'
'Cerny P'
_journal_name_full 'The Canadian Mineralogist'
_journal_volume 29 
_journal_year 1991
_journal_page_first 271
_journal_page_last 285
_publ_section_title
;
 The incorporation of alkalis in beryl: multi-nuclear MAS NMR
 and crystal-structure study
 Sample: EEE-10
;
_database_code_amcsd 0005259
_chemical_compound_source 'Bernic Lake, Manitoba, Canada'
_chemical_formula_sum 'Si6 Be2.79 Li.54 Al2 O18 Na.23 Cs.08'
_cell_length_a 9.202
_cell_length_b 9.202
_cell_length_c 9.207
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 675.170
_exptl_crystal_density_diffrn      2.731
_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   0.38880   0.11810   0.00000   1.00000   0.00510
Be   0.50000   0.00000   0.25000   0.93000   0.00940
Li   0.50000   0.00000   0.25000   0.07000   0.00940
Al   0.66667   0.33333   0.25000   1.00000   0.00540
O1   0.30640   0.23540   0.00000   1.00000   0.01190
O2   0.49840   0.14680   0.14480   1.00000   0.01020
Na   0.00000   0.00000   0.00000   0.23000   0.01290
Li   0.00000   0.00000   0.00000   0.33000   0.01290
Cs   0.00000   0.00000   0.25000   0.08000   0.04840