data_2002407
_chemical_name_systematic          'Barium iron(III) niobium oxide (3/2/6/21)'
_chemical_formula_structural       'Ba3 Fe2 Nb6 O21'
_chemical_formula_sum              'Ba3 Fe2 Nb6 O21'
_publ_section_title
;
Kristallstrukturuntersuchungen an Verbindungen des Typs A3 (M, Nb)8 O21
(A= Tl, Ba; M= Fe, Ni).
;
loop_
_publ_author_name
  'Brandt, R'
  'Mueller-Buschbaum, Hk'
_journal_name_full
;
Zeitschrift fuer Anorganische und Allgemeine Chemie
;
_journal_volume                    556
_journal_year                      1988
_journal_page_first                146
_journal_page_last                 152
_cell_length_a                     9.118(2)
_cell_length_b                     9.118(2)
_cell_length_c                     11.870(1)
_cell_angle_alpha                  90
_cell_angle_beta                   90
_cell_angle_gamma                  120
_cell_volume                       854.6
_cell_formula_units_Z              2
_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
  Nb5+   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 0.5950(2) 0. 0.25 1.  0 d
  Nb1   Nb5+  12 k 0.2455(2) 0. 0.0944(1) 0.75  0 d
  Nb2   Nb5+   4 d 0.33333 0.66667 0. 0.75  0 d
  Fe1   Fe3+  12 k 0.2455(2) 0. 0.0944(1) 0.25  0 d
  Fe2   Fe3+   4 d 0.33333 0.66667 0. 0.25  0 d
  O1    O2-    6 g 0.207(1) 0. 0.25 1.  0 d
  O2    O2-   12 k 0.801(1) 0. 0.071(1) 1.  0 d
  O3    O2-   24 l 0.161(1) 0.483(1) 0.102(1) 1.  0 d
_refine_ls_R_factor_all            0.066