data_global
_chemical_name_mineral 'Chkalovite'
loop_
_publ_author_name
'Simonov M A'
'Egorov-Tismenko Y K'
'Belov N V'
_journal_name_full 'Doklady Akademii Nauk SSSR'
_journal_volume 225 
_journal_year 1975
_journal_page_first 1319
_journal_page_last 1322
_publ_section_title
;
 Utochnennaya kristallicheskaya struktura chkalovita Na2Be[Si2O6]
;
_database_code_amcsd 0012452
_chemical_formula_sum 'Na2 Be Si2 O6'
_cell_length_a 21.129
_cell_length_b 6.881
_cell_length_c 21.1880
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 3080.495
_exptl_crystal_density_diffrn      2.680
_symmetry_space_group_name_H-M 'F d d 2'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  'x,1/2+y,1/2+z'
  '1/2+x,y,1/2+z'
  '1/2+x,1/2+y,z'
  '1/4+x,1/4-y,1/4+z'
  '1/4+x,3/4-y,3/4+z'
  '3/4+x,1/4-y,3/4+z'
  '3/4+x,3/4-y,1/4+z'
  '1/4-x,1/4+y,1/4+z'
  '1/4-x,3/4+y,3/4+z'
  '3/4-x,1/4+y,3/4+z'
  '3/4-x,3/4+y,1/4+z'
  '-x,1/2-y,1/2+z'
  '-x,-y,+z'
  '1/2-x,1/2-y,+z'
  '1/2-x,-y,1/2+z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_U_iso_or_equiv
Na1   0.00000   0.00000   0.51160   0.01317
Na2   0.00000   0.00000   0.14020   0.01203
Na3   0.17320   0.00470   0.03060   0.01102
Na4   0.15820   0.01120   0.66460   0.00937
Be1   0.16850   0.01800   0.82590   0.00494
Be2   0.00000   0.00000   0.36490   0.00671
Si1   0.00000   0.00000   0.00000   0.00203
Si2   0.00000   0.50000   0.16010   0.00177
Si3   0.15000   0.01240   0.17540   0.00190
Si4   0.18370   0.50680   0.01180   0.00190
O1   0.01430   0.18860   0.70760   0.00646
O2   0.11110   0.08520   0.11540   0.00633
O3   0.18900   0.20140   0.20380   0.00671
O4   0.15090   0.20500   0.48160   0.00608
O5   0.22260   0.06970   0.57280   0.00532
O6   0.18830   0.19970   0.87030   0.00532
O7   0.11670   0.08430   0.77130   0.00519
O8   0.01790   0.18830   0.04060   0.00481
O9   0.05460   0.08080   0.41280   0.00519