The material described by BaCaTbBiO6 crystallizes in the orthorhombic P222 space group. There are four inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to four equivalent O(1), four equivalent O(2), and four equivalent O(3) atoms to form BaO12 cuboctahedra that share faces with four equivalent Tb(1)O6 octahedra and faces with four equivalent Bi(1)O6 octahedra. In the second Ba site, Ba(2) is bonded to four equivalent O(4), four equivalent O(5), and four equivalent O(6) atoms to form BaO12 cuboctahedra that share faces with four equivalent Tb(1)O6 octahedra and faces with four equivalent Bi(1)O6 octahedra. In the third Ba site, Ba(3) is bonded in a distorted square co-planar geometry to four equivalent O(2) and four equivalent O(4) atoms. In the fourth Ba site, Ba(4) is bonded in a distorted body-centered cubic geometry to four equivalent O(3) and four equivalent O(5) atoms. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a distorted square co-planar geometry to four equivalent O(5) atoms. In the second Ca site, Ca(2) is bonded in a distorted square co-planar geometry to four equivalent O(2) and four equivalent O(6) atoms. In the third Ca site, Ca(3) is bonded in a square co-planar geometry to four equivalent O(4) atoms. In the fourth Ca site, Ca(4) is bonded in a square co-planar geometry to four equivalent O(1) atoms. Tb(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form TbO6 octahedra that share corners with six equivalent Bi(1)O6 octahedra,  a faceface with one Ba(1)O12 cuboctahedra, and  a faceface with one Ba(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 19-34°. Bi(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form BiO6 octahedra that share corners with six equivalent Tb(1)O6 octahedra,  a faceface with one Ba(1)O12 cuboctahedra, and  a faceface with one Ba(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 19-34°. There are six inequivalent O sites. In the first O site, O(5) is bonded in a 3-coordinate geometry to one Ba(2), one Ba(4), one Ca(1), one Tb(1), and one Bi(1) atom. In the second O site, O(6) is bonded in a 3-coordinate geometry to one Ba(2), one Ca(2), one Tb(1), and one Bi(1) atom. In the third O site, O(1) is bonded in a 3-coordinate geometry to one Ba(1), one Ca(4), one Tb(1), and one Bi(1) atom. In the fourth O site, O(2) is bonded in a 5-coordinate geometry to one Ba(1), one Ba(3), one Ca(2), one Tb(1), and one Bi(1) atom. In the fifth O site, O(3) is bonded in a 4-coordinate geometry to one Ba(1), one Ba(4), one Tb(1), and one Bi(1) atom. In the sixth O site, O(4) is bonded in a 5-coordinate geometry to one Ba(2), one Ba(3), one Ca(3), one Tb(1), and one Bi(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_BaCaTbBiO6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.571
_cell_length_b   8.552
_cell_length_c   8.548
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   626.541
_cell_formula_units_Z   4
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
  Ba  Ba0  1  0.000  0.000  0.000  1.0
  Ba  Ba1  1  0.500  0.500  0.500  1.0
  Ba  Ba2  1  0.500  0.000  0.000  1.0
  Ba  Ba3  1  0.000  0.500  0.000  1.0
  Ca  Ca4  1  0.000  0.500  0.500  1.0
  Ca  Ca5  1  0.500  0.000  0.500  1.0
  Ca  Ca6  1  0.500  0.500  0.000  1.0
  Ca  Ca7  1  0.000  0.000  0.500  1.0
  Tb  Tb8  1  0.251  0.251  0.255  1.0
  Tb  Tb9  1  0.749  0.749  0.255  1.0
  Tb  Tb10  1  0.749  0.251  0.745  1.0
  Tb  Tb11  1  0.251  0.749  0.745  1.0
  Bi  Bi12  1  0.749  0.749  0.744  1.0
  Bi  Bi13  1  0.251  0.251  0.744  1.0
  Bi  Bi14  1  0.251  0.749  0.256  1.0
  Bi  Bi15  1  0.749  0.251  0.256  1.0
  O  O16  1  0.992  0.204  0.300  1.0
  O  O17  1  0.008  0.796  0.300  1.0
  O  O18  1  0.008  0.204  0.700  1.0
  O  O19  1  0.992  0.796  0.700  1.0
  O  O20  1  0.282  0.995  0.222  1.0
  O  O21  1  0.282  0.005  0.778  1.0
  O  O22  1  0.718  0.005  0.222  1.0
  O  O23  1  0.718  0.995  0.778  1.0
  O  O24  1  0.216  0.275  0.992  1.0
  O  O25  1  0.784  0.275  0.008  1.0
  O  O26  1  0.216  0.725  0.008  1.0
  O  O27  1  0.784  0.725  0.992  1.0
  O  O28  1  0.508  0.307  0.207  1.0
  O  O29  1  0.492  0.693  0.207  1.0
  O  O30  1  0.492  0.307  0.793  1.0
  O  O31  1  0.508  0.693  0.793  1.0
  O  O32  1  0.201  0.508  0.304  1.0
  O  O33  1  0.201  0.492  0.696  1.0
  O  O34  1  0.799  0.492  0.304  1.0
  O  O35  1  0.799  0.508  0.696  1.0
  O  O36  1  0.311  0.207  0.506  1.0
  O  O37  1  0.689  0.207  0.494  1.0
  O  O38  1  0.311  0.793  0.494  1.0
  O  O39  1  0.689  0.793  0.506  1.0
[/CIF]
.
The material described by BaCaTbBiO6 crystallizes in the orthorhombic P222 space group. There are four inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to four equivalent O(1), four equivalent O(2), and four equivalent O(3) atoms to form BaO12 cuboctahedra that share faces with four equivalent Tb(1)O6 octahedra and faces with four equivalent Bi(1)O6 octahedra. In the second Ba site, Ba(2) is bonded to four equivalent O(4), four equivalent O(5), and four equivalent O(6) atoms to form BaO12 cuboctahedra that share faces with four equivalent Tb(1)O6 octahedra and faces with four equivalent Bi(1)O6 octahedra. In the third Ba site, Ba(3) is bonded in a distorted square co-planar geometry to four equivalent O(2) and four equivalent O(4) atoms. In the fourth Ba site, Ba(4) is bonded in a distorted body-centered cubic geometry to four equivalent O(3) and four equivalent O(5) atoms. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a distorted square co-planar geometry to four equivalent O(5) atoms. In the second Ca site, Ca(2) is bonded in a distorted square co-planar geometry to four equivalent O(2) and four equivalent O(6) atoms. In the third Ca site, Ca(3) is bonded in a square co-planar geometry to four equivalent O(4) atoms. In the fourth Ca site, Ca(4) is bonded in a square co-planar geometry to four equivalent O(1) atoms. Tb(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form TbO6 octahedra that share corners with six equivalent Bi(1)O6 octahedra,  a faceface with one Ba(1)O12 cuboctahedra, and  a faceface with one Ba(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 19-34°. Bi(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form BiO6 octahedra that share corners with six equivalent Tb(1)O6 octahedra,  a faceface with one Ba(1)O12 cuboctahedra, and  a faceface with one Ba(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 19-34°. There are six inequivalent O sites. In the first O site, O(5) is bonded in a 3-coordinate geometry to one Ba(2), one Ba(4), one Ca(1), one Tb(1), and one Bi(1) atom. In the second O site, O(6) is bonded in a 3-coordinate geometry to one Ba(2), one Ca(2), one Tb(1), and one Bi(1) atom. In the third O site, O(1) is bonded in a 3-coordinate geometry to one Ba(1), one Ca(4), one Tb(1), and one Bi(1) atom. In the fourth O site, O(2) is bonded in a 5-coordinate geometry to one Ba(1), one Ba(3), one Ca(2), one Tb(1), and one Bi(1) atom. In the fifth O site, O(3) is bonded in a 4-coordinate geometry to one Ba(1), one Ba(4), one Tb(1), and one Bi(1) atom. In the sixth O site, O(4) is bonded in a 5-coordinate geometry to one Ba(2), one Ba(3), one Ca(3), one Tb(1), and one Bi(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_BaCaTbBiO6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.571
_cell_length_b   8.552
_cell_length_c   8.548
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   626.541
_cell_formula_units_Z   4
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
  Ba  Ba0  1  0.000  0.000  0.000  1.0
  Ba  Ba1  1  0.500  0.500  0.500  1.0
  Ba  Ba2  1  0.500  0.000  0.000  1.0
  Ba  Ba3  1  0.000  0.500  0.000  1.0
  Ca  Ca4  1  0.000  0.500  0.500  1.0
  Ca  Ca5  1  0.500  0.000  0.500  1.0
  Ca  Ca6  1  0.500  0.500  0.000  1.0
  Ca  Ca7  1  0.000  0.000  0.500  1.0
  Tb  Tb8  1  0.251  0.251  0.255  1.0
  Tb  Tb9  1  0.749  0.749  0.255  1.0
  Tb  Tb10  1  0.749  0.251  0.745  1.0
  Tb  Tb11  1  0.251  0.749  0.745  1.0
  Bi  Bi12  1  0.749  0.749  0.744  1.0
  Bi  Bi13  1  0.251  0.251  0.744  1.0
  Bi  Bi14  1  0.251  0.749  0.256  1.0
  Bi  Bi15  1  0.749  0.251  0.256  1.0
  O  O16  1  0.992  0.204  0.300  1.0
  O  O17  1  0.008  0.796  0.300  1.0
  O  O18  1  0.008  0.204  0.700  1.0
  O  O19  1  0.992  0.796  0.700  1.0
  O  O20  1  0.282  0.995  0.222  1.0
  O  O21  1  0.282  0.005  0.778  1.0
  O  O22  1  0.718  0.005  0.222  1.0
  O  O23  1  0.718  0.995  0.778  1.0
  O  O24  1  0.216  0.275  0.992  1.0
  O  O25  1  0.784  0.275  0.008  1.0
  O  O26  1  0.216  0.725  0.008  1.0
  O  O27  1  0.784  0.725  0.992  1.0
  O  O28  1  0.508  0.307  0.207  1.0
  O  O29  1  0.492  0.693  0.207  1.0
  O  O30  1  0.492  0.307  0.793  1.0
  O  O31  1  0.508  0.693  0.793  1.0
  O  O32  1  0.201  0.508  0.304  1.0
  O  O33  1  0.201  0.492  0.696  1.0
  O  O34  1  0.799  0.492  0.304  1.0
  O  O35  1  0.799  0.508  0.696  1.0
  O  O36  1  0.311  0.207  0.506  1.0
  O  O37  1  0.689  0.207  0.494  1.0
  O  O38  1  0.311  0.793  0.494  1.0
  O  O39  1  0.689  0.793  0.506  1.0
[/CIF]
.