data_global
_amcsd_formula_title 'Ba K4 O26 Si4 Ta6'
loop_
_publ_author_name
'Choisnet J'
'Nguyen N'
'Raveau B'
_journal_name_full 'Materials Research Bulletin'
_journal_volume 12 
_journal_year 1977
_journal_page_first 91
_journal_page_last 96
_publ_section_title
;
 Silicotantalates et siliconiobates non-stoechiometriques: les composes
 K6-2x Bax Ta6 Si4 O26 (0<x<3) et K8 M14 Si4 O47 (M = Ta, Nb)
 _cod_database_code 1001274
;
_database_code_amcsd 0014254
_chemical_formula_sum '(Ba K4) Ta6 Si4 O26'
_cell_length_a 9.047
_cell_length_b 9.047
_cell_length_c 7.81
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 553.593
_exptl_crystal_density_diffrn      5.722
_symmetry_space_group_name_H-M 'P -6 2 m'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '-x,-x+y,z'
  '-x+y,-x,-z'
  'y,x,-z'
  '-y,x-y,z'
  'x-y,-y,z'
  'x,y,-z'
  '-x,-x+y,-z'
  '-x+y,-x,z'
  'y,x,z'
  '-y,x-y,-z'
  'x-y,-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
Ba1   0.58600   0.00000   0.50000   0.33330
K1   0.58600   0.00000   0.50000   0.66670
K2   0.61000   0.00000   0.00000   0.66670
Ta1   0.23900   0.00000   0.24900   1.00000
Si1   0.33333   0.66667   0.20800   1.00000
O1   0.33333   0.66667   0.00000   1.00000
O2   0.26200   0.00000   0.00000   1.00000
O3   0.81100   0.00000   0.26900   1.00000
O4   0.50000   0.17600   0.28900   1.00000
O5   0.24200   0.00000   0.50000   1.00000