The structure described by CaBi2Ta2O9 crystallizes in the orthorhombic Cmc2_1 space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(3), and four equivalent O(5) atoms. Ta(1) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(5) atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 25-31°. Bi(1) is bonded in a 6-coordinate geometry to two equivalent O(1) and four equivalent O(4) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Ta(1) and two equivalent Bi(1) atoms. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Ca(1) and two equivalent Ta(1) atoms. In the third O site, O(3) is bonded to two equivalent Ca(1) and two equivalent Ta(1) atoms to form a mixture of distorted corner and edge-sharing OCa2Ta2 tetrahedra. In the fourth O site, O(4) is bonded to four equivalent Bi(1) atoms to form a mixture of corner and edge-sharing OBi4 tetrahedra. In the fifth O site, O(5) is bonded to two equivalent Ca(1) and two equivalent Ta(1) atoms to form a mixture of distorted corner and edge-sharing OCa2Ta2 trigonal pyramids. is represented by the CIF card [CIF]
data_CaTa2Bi2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.972
_cell_length_b   12.972
_cell_length_c   5.556
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   155.548
_symmetry_Int_Tables_number   1
_cell_volume   387.004
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Ca  Ca0  1  0.755  0.755  0.499  1.0
  Ca  Ca1  1  0.245  0.245  0.999  1.0
  Ta  Ta2  1  0.829  0.667  0.034  1.0
  Ta  Ta3  1  0.171  0.333  0.534  1.0
  Ta  Ta4  1  0.333  0.171  0.534  1.0
  Ta  Ta5  1  0.667  0.829  0.034  1.0
  Bi  Bi6  1  0.019  0.417  0.957  1.0
  Bi  Bi7  1  0.417  0.019  0.957  1.0
  Bi  Bi8  1  0.583  0.981  0.457  1.0
  Bi  Bi9  1  0.981  0.583  0.457  1.0
  O  O10  1  0.679  0.986  0.052  1.0
  O  O11  1  0.539  0.367  0.845  1.0
  O  O12  1  0.672  0.672  0.073  1.0
  O  O13  1  0.328  0.328  0.573  1.0
  O  O14  1  0.367  0.539  0.845  1.0
  O  O15  1  0.263  0.762  0.233  1.0
  O  O16  1  0.014  0.321  0.552  1.0
  O  O17  1  0.975  0.097  0.268  1.0
  O  O18  1  0.097  0.975  0.268  1.0
  O  O19  1  0.633  0.461  0.345  1.0
  O  O20  1  0.321  0.014  0.552  1.0
  O  O21  1  0.025  0.903  0.768  1.0
  O  O22  1  0.737  0.238  0.733  1.0
  O  O23  1  0.461  0.633  0.345  1.0
  O  O24  1  0.238  0.737  0.733  1.0
  O  O25  1  0.903  0.025  0.768  1.0
  O  O26  1  0.986  0.679  0.052  1.0
  O  O27  1  0.762  0.263  0.233  1.0
[/CIF]
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The structure described by CaBi2Ta2O9 crystallizes in the orthorhombic Cmc2_1 space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(3), and four equivalent O(5) atoms. Ta(1) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(5) atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 25-31°. Bi(1) is bonded in a 6-coordinate geometry to two equivalent O(1) and four equivalent O(4) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Ta(1) and two equivalent Bi(1) atoms. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Ca(1) and two equivalent Ta(1) atoms. In the third O site, O(3) is bonded to two equivalent Ca(1) and two equivalent Ta(1) atoms to form a mixture of distorted corner and edge-sharing OCa2Ta2 tetrahedra. In the fourth O site, O(4) is bonded to four equivalent Bi(1) atoms to form a mixture of corner and edge-sharing OBi4 tetrahedra. In the fifth O site, O(5) is bonded to two equivalent Ca(1) and two equivalent Ta(1) atoms to form a mixture of distorted corner and edge-sharing OCa2Ta2 trigonal pyramids. is represented by the CIF card [CIF]
data_CaTa2Bi2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.972
_cell_length_b   12.972
_cell_length_c   5.556
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   155.548
_symmetry_Int_Tables_number   1
_cell_volume   387.004
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Ca  Ca0  1  0.755  0.755  0.499  1.0
  Ca  Ca1  1  0.245  0.245  0.999  1.0
  Ta  Ta2  1  0.829  0.667  0.034  1.0
  Ta  Ta3  1  0.171  0.333  0.534  1.0
  Ta  Ta4  1  0.333  0.171  0.534  1.0
  Ta  Ta5  1  0.667  0.829  0.034  1.0
  Bi  Bi6  1  0.019  0.417  0.957  1.0
  Bi  Bi7  1  0.417  0.019  0.957  1.0
  Bi  Bi8  1  0.583  0.981  0.457  1.0
  Bi  Bi9  1  0.981  0.583  0.457  1.0
  O  O10  1  0.679  0.986  0.052  1.0
  O  O11  1  0.539  0.367  0.845  1.0
  O  O12  1  0.672  0.672  0.073  1.0
  O  O13  1  0.328  0.328  0.573  1.0
  O  O14  1  0.367  0.539  0.845  1.0
  O  O15  1  0.263  0.762  0.233  1.0
  O  O16  1  0.014  0.321  0.552  1.0
  O  O17  1  0.975  0.097  0.268  1.0
  O  O18  1  0.097  0.975  0.268  1.0
  O  O19  1  0.633  0.461  0.345  1.0
  O  O20  1  0.321  0.014  0.552  1.0
  O  O21  1  0.025  0.903  0.768  1.0
  O  O22  1  0.737  0.238  0.733  1.0
  O  O23  1  0.461  0.633  0.345  1.0
  O  O24  1  0.238  0.737  0.733  1.0
  O  O25  1  0.903  0.025  0.768  1.0
  O  O26  1  0.986  0.679  0.052  1.0
  O  O27  1  0.762  0.263  0.233  1.0
[/CIF]
.