data_9004120
_chemical_name 'Beryl'
loop_
_publ_author_name
'Hawthorne F C'
'Cerny P'
_journal_name_full "The Canadian Mineralogist"
_journal_volume 15
_journal_year 1977
_journal_page_first 414
_journal_page_last 421
_publ_section_title
;
 The alkali-metal positions in Cs-Li beryl
;
_chemical_formula_sum 'Si5.958 Be2.613 Li.436 Al2 O18.66 Na.313 K.033 Rb.006 Ca.
_cell_length_a 9.212
_cell_length_b 9.212
_cell_length_c 9.236
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 678.770
_symmetry_space_group_name_H-M 'P 6/m c c'
loop_
_symmetry_equiv_pos_as_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_Uiso_or_equiv
Si   0.38920   0.11890   0.00000   0.99300 ?
Be   0.50000   0.00000   0.25000   0.87100 ?
Li   0.50000   0.00000   0.25000   0.12900 ?
Al   0.66667   0.33333   0.25000   1.00000 ?
O1   0.30480   0.23520   0.00000   1.00000 ?
O2   0.49830   0.14730   0.14450   1.00000 ?
Na   0.00000   0.00000   0.00000   0.31300   0.03166
K   0.00000   0.00000   0.00000   0.03300   0.03166
Rb   0.00000   0.00000   0.00000   0.00600   0.03166
Ca   0.00000   0.00000   0.00000   0.00300   0.03166
Li   0.00000   0.00000   0.00000   0.04900   0.03166
Cs   0.00000   0.00000   0.25000   0.13400   0.03166
Wat   0.00000   0.00000   0.25000   0.66000   0.03166