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: 19
 Note: U(1,2) for Na/Cs/Rb altered to match symmetry constraints.
;
_database_code_amcsd 0001182
_chemical_compound_source 'Salinas mine, Minas Gerais, Brazil'
_chemical_formula_sum 'Si6.003 Be2.595 Li.393 Al2.009 O18 Na.239 Cs.131 Rb.002'
_cell_length_a 9.2155
_cell_length_b 9.2155
_cell_length_c 9.2291
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 678.778
_exptl_crystal_density_diffrn      2.740
_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
Si1   0.38940   0.11910   0.00000   1.00000 ?
Be   0.50000   0.00000   0.25000   0.86500   0.00700
Li   0.50000   0.00000   0.25000   0.13100   0.00700
Si2   0.50000   0.00000   0.25000   0.00100   0.00700
Al1   0.50000   0.00000   0.25000   0.00300   0.00700
Al2   0.66667   0.33333   0.25000   1.00000 ?
O1   0.30510   0.23480   0.00000   1.00000 ?
O2   0.49810   0.14700   0.14470   1.00000 ?
Na   0.00000   0.00000   0.25000   0.23900 ?
Cs   0.00000   0.00000   0.25000   0.13100 ?
Rb   0.00000   0.00000   0.25000   0.00200 ?
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
Si1 0.00290 0.00290 0.00430 0.00160 0.00000 0.00000
Al2 0.00320 0.00320 0.00450 0.00160 0.00000 0.00000
O1 0.01040 0.00870 0.01920 0.00750 0.00000 0.00000
O2 0.01180 0.01140 0.01000 0.00730 -0.00570 -0.00400
Na 0.01870 0.01870 0.01620 0.00935 0.00000 0.00000
Cs 0.01870 0.01870 0.01620 0.00935 0.00000 0.00000
Rb 0.01870 0.01870 0.01620 0.00935 0.00000 0.00000