The compound described by CaBi2Ta2O9 crystallizes in the triclinic P-1 space group. Ca(1) is bonded to four equivalent O(2), four equivalent O(4), and four equivalent O(5) atoms to form CaO12 cuboctahedra that share corners with four equivalent Ca(1)O12 cuboctahedra, faces with four equivalent Ca(1)O12 cuboctahedra, and faces with eight equivalent Ta(1)O6 octahedra. Ta(1) is bonded to one O(1), one O(5), two equivalent O(2), and two equivalent O(4) atoms to form TaO6 octahedra that share corners with five equivalent Ta(1)O6 octahedra and faces with four equivalent Ca(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-14°. Bi(1) is bonded in a 5-coordinate geometry to one O(1) and four equivalent O(3) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Ta(1) and one Bi(1) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ca(1) and two equivalent Ta(1) atoms. In the third O site, O(3) is bonded to four equivalent Bi(1) atoms to form a mixture of corner and edge-sharing OBi4 tetrahedra. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ca(1) and two equivalent Ta(1) atoms. In the fifth O site, O(5) is bonded in a distorted linear geometry to four equivalent Ca(1) and two equivalent Ta(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_CaTa2Bi2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.938
_cell_length_b   3.955
_cell_length_c   13.055
_cell_angle_alpha   94.289
_cell_angle_beta   96.405
_cell_angle_gamma   90.024
_symmetry_Int_Tables_number   1
_cell_volume   201.461
_cell_formula_units_Z   1
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  0.500  0.500  0.000  1.0
  Ta  Ta1  1  0.062  0.049  0.160  1.0
  Ta  Ta2  1  0.938  0.951  0.840  1.0
  Bi  Bi3  1  0.256  0.236  0.599  1.0
  Bi  Bi4  1  0.744  0.764  0.401  1.0
  O  O5  1  0.107  0.067  0.308  1.0
  O  O6  1  0.893  0.933  0.692  1.0
  O  O7  1  0.550  0.038  0.142  1.0
  O  O8  1  0.755  0.247  0.498  1.0
  O  O9  1  0.245  0.753  0.502  1.0
  O  O10  1  0.044  0.538  0.142  1.0
  O  O11  1  0.450  0.962  0.858  1.0
  O  O12  1  0.956  0.462  0.858  1.0
  O  O13  1  0.000  0.000  0.000  1.0
[/CIF]
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The compound described by CaBi2Ta2O9 crystallizes in the triclinic P-1 space group. Ca(1) is bonded to four equivalent O(2), four equivalent O(4), and four equivalent O(5) atoms to form CaO12 cuboctahedra that share corners with four equivalent Ca(1)O12 cuboctahedra, faces with four equivalent Ca(1)O12 cuboctahedra, and faces with eight equivalent Ta(1)O6 octahedra. Ta(1) is bonded to one O(1), one O(5), two equivalent O(2), and two equivalent O(4) atoms to form TaO6 octahedra that share corners with five equivalent Ta(1)O6 octahedra and faces with four equivalent Ca(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-14°. Bi(1) is bonded in a 5-coordinate geometry to one O(1) and four equivalent O(3) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Ta(1) and one Bi(1) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ca(1) and two equivalent Ta(1) atoms. In the third O site, O(3) is bonded to four equivalent Bi(1) atoms to form a mixture of corner and edge-sharing OBi4 tetrahedra. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ca(1) and two equivalent Ta(1) atoms. In the fifth O site, O(5) is bonded in a distorted linear geometry to four equivalent Ca(1) and two equivalent Ta(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_CaTa2Bi2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.938
_cell_length_b   3.955
_cell_length_c   13.055
_cell_angle_alpha   94.289
_cell_angle_beta   96.405
_cell_angle_gamma   90.024
_symmetry_Int_Tables_number   1
_cell_volume   201.461
_cell_formula_units_Z   1
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  0.500  0.500  0.000  1.0
  Ta  Ta1  1  0.062  0.049  0.160  1.0
  Ta  Ta2  1  0.938  0.951  0.840  1.0
  Bi  Bi3  1  0.256  0.236  0.599  1.0
  Bi  Bi4  1  0.744  0.764  0.401  1.0
  O  O5  1  0.107  0.067  0.308  1.0
  O  O6  1  0.893  0.933  0.692  1.0
  O  O7  1  0.550  0.038  0.142  1.0
  O  O8  1  0.755  0.247  0.498  1.0
  O  O9  1  0.245  0.753  0.502  1.0
  O  O10  1  0.044  0.538  0.142  1.0
  O  O11  1  0.450  0.962  0.858  1.0
  O  O12  1  0.956  0.462  0.858  1.0
  O  O13  1  0.000  0.000  0.000  1.0
[/CIF]
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