data_2002790
_chemical_name_systematic          'Dibarium hexanioboditellurate(IV)'
_chemical_formula_structural       'Ba2 (Nb6 Te2 O21)'
_chemical_formula_sum              'Ba2 Nb6 O21 Te2'
_publ_section_title
;
Zur Kristallchemie der Barium-Oxometallat-Tellurite: Ba2 Te2 M6 O21 (M
= Niob und Tantal )
;
loop_
_publ_author_name
  'Mueller-Buschbaum, Hk'
  'Wedel, B'
_journal_name_full
;
Zeitschrift fuer Naturforschung, Teil B. Anorganische Chemie,
Organische Chemie (42,1987-)
;
_journal_volume                    51
_journal_year                      1996
_journal_page_first                1411
_journal_page_last                 1414
_cell_length_a                     16.69899(300)
_cell_length_b                     5.671(2)
_cell_length_c                     9.611(2)
_cell_angle_alpha                  90
_cell_angle_beta                   96.92(2)
_cell_angle_gamma                  90
_cell_volume                       903.5
_cell_formula_units_Z              2
_symmetry_space_group_name_H-M     'C 1 2/m 1'
_symmetry_Int_Tables_number        12
_symmetry_cell_setting             monoclinic
loop_
_symmetry_equiv_pos_as_xyz
  'x,y,z'
  'x,-y,z'
  '-x,-y,-z'
  '-x,y,-z'
  '1/2+x,1/2+y,z'
  '1/2+x,1/2-y,z'
  '1/2-x,1/2-y,-z'
  '1/2-x,1/2+y,-z'
loop_
_atom_type_symbol
_atom_type_oxidation_number
  Ba2+   2.000
  Te4+   4.000
  Nb5+   5.000
  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 i 0.138570(3) 0. 0.523080(5) 1.  0 d
  Te1   Te4+   4 i 0.275630(3) 0. 0.246390(5) 1.  0 d
  Nb1   Nb5+   4 i 0.401670(4) -0.5 0.083320(8) 1.  0 d
  Nb2   Nb5+   4 i 0.519850(4) 0. -0.336630(7) 1.  0 d
  Nb3   Nb5+   4 i 0.323810(4) 0. -0.170680(7) 1.  0 d
  O1    O2-    4 h 0.5 0.22205(11) -0.5 1.  0 d
  O2    O2-    4 i 0.35869(4) 0. 0.39617(7) 1.  0 d
  O3    O2-    8 j 0.21959(3) 0.2430(1) 0.32904(5) 1.  0 d
  O4    O2-    8 j 0.35579(3) 0.25148(10) -0.05474(5) 1.  0 d
  O5    O2-    8 j 0.56672(3) -0.25945(10) -0.22016(5) 1.  0 d
  O6    O2-    2 a 0.5 -0.5 0. 1.  0 d
  O7    O2-    4 i 0.20958(4) 0. -0.14595(8) 1.  0 d
  O8    O2-    4 i 0.41821(4) 0. -0.28166(8) 1.  0 d
loop_
_atom_site_aniso_label
_atom_site_aniso_U_11
_atom_site_aniso_U_12
_atom_site_aniso_U_13
_atom_site_aniso_U_22
_atom_site_aniso_U_23
_atom_site_aniso_U_33
  Ba1   0.01176(2) 0. 0.00372(1) 0.01159(2) 0. 0.01574(2)
  Te1   0.00976(2) 0. 0.00135(1) 0.00880(2) 0. 0.00877(2)
  Nb1   0.01205(3) 0. 0.00006(2) 0.00896(3) 0. 0.01024(2)
  Nb2   0.00773(2) 0. 0.00131(2) 0.00965(3) 0. 0.00864(2)
  Nb3   0.00903(2) 0. 0.00023(2) 0.00628(2) 0. 0.00836(2)
  O1    0.0114(2) 0. 0.0010(2) 0.0104(2) 0. 0.0110(2)
  O2    0.0164(2) 0. 0.0021(2) 0.0201(3) 0. 0.0165(3)
  O3    0.0185(2) 0.0014(2) 0.00254(14) 0.0164(2) 0.0008(2) 0.0169(2)
  O4    0.0229(2) -0.0014(2) 0.0024(2) 0.0210(2) -0.0012(2) 0.0214(2)
  O5    0.0236(2) 0.0010(2) 0.0015(2) 0.0205(2) 0.0009(2) 0.0215(2)
  O6    0.0210(4) 0. 0.0042(3) 0.0253(5) 0. 0.0221(4)
  O7    0.0218(3) 0. 0.0037(3) 0.0256(4) 0. 0.0235(3)
  O8    0.0194(3) 0. 0.0029(2) 0.0235(3) 0. 0.0197(3)
_refine_ls_R_factor_all            0.0491