data_1008169
_chemical_name_systematic          'Barium dichromate - $-alpha'
_chemical_formula_structural       'Ba Cr2 O7'
_chemical_formula_sum              'Ba Cr2 O7'
_publ_section_title
;
Structure du Dichromate de Baryum, Form $-alpha
;
loop_
_publ_author_name
  'Blum, D'
  'Averbuch-Pouchot, M T'
  'Guitel, J C'
_journal_name_full                 'Acta Crystallographica B (24,1968-38,1982)'
_journal_coden_ASTM                ACBCAR
_journal_volume                    35
_journal_year                      1979
_journal_page_first                2685
_journal_page_last                 2687
_cell_length_a                     16.31(2)
_cell_length_b                     16.67(2)
_cell_length_c                     9.474(5)
_cell_angle_alpha                  90
_cell_angle_beta                   95.53(5)
_cell_angle_gamma                  90
_cell_volume                       2563.9
_cell_formula_units_Z              16
_symmetry_space_group_name_H-M     'C 1 2/c 1'
_symmetry_Int_Tables_number        15
_symmetry_cell_setting             monoclinic
loop_
_symmetry_equiv_pos_as_xyz
  'x,y,z'
  '-x,y,1/2-z'
  '-x,-y,-z'
  'x,-y,1/2+z'
  '1/2+x,1/2+y,z'
  '1/2-x,1/2+y,1/2-z'
  '1/2-x,1/2-y,-z'
  '1/2+x,1/2-y,1/2+z'
loop_
_atom_type_symbol
_atom_type_oxidation_number
  Ba2+   2.000
  Cr6+   6.000
  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+   4 e 0. 0.45992(3) 0.25 1.  0 d
  Ba2   Ba2+   4 e 0. 0.04261(3) 0.25 1.  0 d
  Ba3   Ba2+   8 f 0.20500(2) 0.75605(2) 0.71895(4) 1.  0 d
  Cr1   Cr6+   8 f 0.17106(6) 0.42198(5) 0.5028(1) 1.  0 d
  Cr2   Cr6+   8 f 0.30709(6) 0.44080(6) 0.0070(1) 1.  0 d
  Cr3   Cr6+   8 f 0.41862(6) 0.32566(6) 0.4593(1) 1.  0 d
  Cr4   Cr6+   8 f 0.43633(5) 0.19075(5) 0.0614(1) 1.  0 d
  O1    O2-    8 f 0.4041(3) 0.0208(3) 0.4527(6) 1.  0 d
  O2    O2-    8 f 0.1361(3) 0.3631(3) 0.3750(6) 1.  0 d
  O3    O2-    8 f 0.2905(4) 0.1265(3) 0.3647(6) 1.  0 d
  O4    O2-    8 f 0.2467(3) 0.4821(3) 0.4288(6) 1.  0 d
  O5    O2-    8 f 0.1366(3) 0.0991(3) 0.1137(6) 1.  0 d
  O6    O2-    8 f 0.2452(3) 0.3736(4) 0.0615(8) 1.  0 d
  O7    O2-    8 f 0.3623(4) 0.4775(4) 0.1339(7) 1.  0 d
  O8    O2-    8 f 0.0778(3) 0.1796(3) 0.3683(5) 1.  0 d
  O9    O2-    8 f 0.4579(4) 0.4114(3) 0.4179(7) 1.  0 d
  O10   O2-    8 f 0.3257(3) 0.3155(4) 0.4002(8) 1.  0 d
  O11   O2-    8 f 0.4743(3) 0.2458(3) 0.3898(6) 1.  0 d
  O12   O2-    8 f 0.3542(3) 0.2430(3) 0.0839(6) 1.  0 d
  O13   O2-    8 f 0.0613(3) 0.3286(3) 0.1078(5) 1.  0 d
  O14   O2-    8 f 0.4360(3) 0.1089(3) 0.1513(6) 1.  0 d
_refine_ls_R_factor_all            0.039