data_1001301
_chemical_name_systematic          'BARIUM TANTALUM IRON OXIDE (3/6/2/21)'
_chemical_formula_structural       'BA3 (TA6 FE2) O21'
_chemical_formula_sum              'Ba3 Fe2 O21 Ta6'
_publ_section_title
;
Nouveaux tantalates A~3~ (Ta~8-x~ M~x~) O~21~ a structure en cages
;
loop_
_publ_author_name
  'Groult, D'
  'Chailleux, J M'
  'Raveau, B'
  'Deschanvres, A'
_journal_name_full                 'Revue de Chimie Minerale'
_journal_coden_ASTM                RVCMA8
_journal_volume                    14
_journal_year                      1977
_journal_page_first                1
_journal_page_last                 10
_cell_length_a                     9.116
_cell_length_b                     9.116
_cell_length_c                     11.93
_cell_angle_alpha                  90
_cell_angle_beta                   90
_cell_angle_gamma                  120
_cell_volume                       858.6
_cell_formula_units_Z              2
_exptl_crystal_density_meas        7.55
_symmetry_space_group_name_H-M     'P 63/m c m'
_symmetry_Int_Tables_number        193
_symmetry_cell_setting             hexagonal
loop_
_symmetry_equiv_pos_as_xyz
  'x,y,z'
  '-y,x-y,z'
  'y-x,-x,z'
  'y,x,z'
  'x-y,-y,z'
  '-x,y-x,z'
  '-x,-y,-z'
  'y,y-x,-z'
  'x-y,x,-z'
  '-y,-x,-z'
  'y-x,y,-z'
  'x,x-y,-z'
  '-x,-y,1/2+z'
  'y,y-x,1/2+z'
  'x-y,x,1/2+z'
  '-y,-x,1/2+z'
  'y-x,y,1/2+z'
  'x,x-y,1/2+z'
  'x,y,1/2-z'
  '-y,x-y,1/2-z'
  'y-x,-x,1/2-z'
  'y,x,1/2-z'
  'x-y,-y,1/2-z'
  '-x,y-x,1/2-z'
loop_
_atom_type_symbol
_atom_type_oxidation_number
  Ba2+   2.000
  Ta5+   5.000
  Fe3+   3.000
  O2-   -2.000
loop_
_atom_site_label
_atom_site_type_symbol
_atom_site_symmetry_multiplicity
_atom_site_Wyckoff_symbol
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
_atom_site_attached_hydrogens
_atom_site_calc_flag
  Ba1   Ba2+   6 g 0.591 0. 0.25 1.  0 d
  Ta1   Ta5+  12 k 0.243 0. 0.094 0.6667  0 d
  Fe1   Fe3+  12 k 0.243 0. 0.094 0.3333  0 d
  Ta2   Ta5+   4 d 0.33333 0.66667 0. 1.  0 d
  O1    O2-    6 g 0.226 0. 0.25 1.  0 d
  O2    O2-   12 k 0.787 0. 0.083 1.  0 d
  O3    O2-   24 i 0.172 0.493 0.108 1.  0 d
_refine_ls_R_factor_all            0.064