The material described by Ba3TiTa4O15 crystallizes in the monoclinic Pc space group. There are three inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one O(12), one O(13), one O(14), one O(15), two equivalent O(3), two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms to form BaO12 cuboctahedra that share faces with two equivalent Ba(1)O12 cuboctahedra, faces with two equivalent Ti(1)O6 octahedra, faces with two equivalent Ta(2)O6 octahedra, faces with two equivalent Ta(3)O6 octahedra, and faces with two equivalent Ta(4)O6 octahedra. In the second Ba site, Ba(2) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(10), and two equivalent O(7) atoms. In the third Ba site, Ba(3) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(8), and two equivalent O(9) atoms. Ti(1) is bonded to one O(1), one O(3), one O(5), one O(9), and two equivalent O(12) atoms to form distorted TiO6 octahedra that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(3)O6 octahedra, corners with two equivalent Ti(1)O6 octahedra, corners with two equivalent Ta(4)O6 octahedra, and faces with two equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 7-39°. There are four inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(10), one O(7), one O(8), one O(9), and two equivalent O(11) atoms to form TaO6 octahedra that share  a cornercorner with one Ti(1)O6 octahedra,  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Ta(3)O6 octahedra,  a cornercorner with one Ta(4)O6 octahedra, and corners with two equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-36°. In the second Ta site, Ta(2) is bonded to one O(10), one O(2), one O(4), one O(6), and two equivalent O(13) atoms to form TaO6 octahedra that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(4)O6 octahedra, corners with two equivalent Ta(2)O6 octahedra, corners with two equivalent Ta(3)O6 octahedra, and faces with two equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 3-37°. In the third Ta site, Ta(3) is bonded to one O(2), one O(4), one O(5), one O(8), and two equivalent O(14) atoms to form TaO6 octahedra that share  a cornercorner with one Ti(1)O6 octahedra,  a cornercorner with one Ta(1)O6 octahedra, corners with two equivalent Ta(2)O6 octahedra, corners with two equivalent Ta(3)O6 octahedra, and faces with two equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 1-37°. In the fourth Ta site, Ta(4) is bonded to one O(1), one O(3), one O(6), one O(7), and two equivalent O(15) atoms to form TaO6 octahedra that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(2)O6 octahedra, corners with two equivalent Ti(1)O6 octahedra, corners with two equivalent Ta(4)O6 octahedra, and faces with two equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 3-39°. There are fifteen inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Ba(2), one Ti(1), and one Ta(4) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Ba(3), one Ta(2), and one Ta(3) atom. In the third O site, O(3) is bonded in a distorted linear geometry to two equivalent Ba(1), one Ti(1), and one Ta(4) atom. In the fourth O site, O(4) is bonded in a distorted linear geometry to two equivalent Ba(1), one Ta(2), and one Ta(3) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to two equivalent Ba(1), one Ti(1), and one Ta(3) atom. In the sixth O site, O(6) is bonded in a distorted linear geometry to two equivalent Ba(1), one Ta(2), and one Ta(4) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to two equivalent Ba(2), one Ta(1), and one Ta(4) atom. In the eighth O site, O(8) is bonded in a distorted bent 150 degrees geometry to two equivalent Ba(3), one Ta(1), and one Ta(3) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to two equivalent Ba(3), one Ti(1), and one Ta(1) atom. In the tenth O site, O(10) is bonded in a distorted bent 150 degrees geometry to two equivalent Ba(2), one Ta(1), and one Ta(2) atom. In the eleventh O site, O(11) is bonded in a linear geometry to two equivalent Ta(1) atoms. In the twelfth O site, O(12) is bonded in a 1-coordinate geometry to one Ba(1) and two equivalent Ti(1) atoms. In the thirteenth O site, O(13) is bonded in a distorted linear geometry to one Ba(1) and two equivalent Ta(2) atoms. In the fourteenth O site, O(14) is bonded in a distorted linear geometry to one Ba(1) and two equivalent Ta(3) atoms. In the fifteenth O site, O(15) is bonded in a distorted linear geometry to one Ba(1) and two equivalent Ta(4) atoms. is represented by the CIF file [CIF]
data_Ba3Ta4TiO15
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.760
_cell_length_b   4.019
_cell_length_c   12.685
_cell_angle_alpha   89.952
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   650.420
_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
  Ba  Ba0  1  0.748  0.705  0.494  1.0
  Ba  Ba1  1  0.252  0.705  0.994  1.0
  Ba  Ba2  1  0.573  0.708  0.829  1.0
  Ba  Ba3  1  0.917  0.706  0.174  1.0
  Ba  Ba4  1  0.083  0.706  0.674  1.0
  Ba  Ba5  1  0.427  0.708  0.329  1.0
  Ta  Ta6  1  0.751  0.200  0.004  1.0
  Ta  Ta7  1  0.249  0.200  0.504  1.0
  Ta  Ta8  1  0.824  0.209  0.714  1.0
  Ta  Ta9  1  0.176  0.209  0.214  1.0
  Ta  Ta10  1  0.960  0.208  0.424  1.0
  Ta  Ta11  1  0.536  0.207  0.574  1.0
  Ta  Ta12  1  0.040  0.208  0.924  1.0
  Ta  Ta13  1  0.464  0.207  0.074  1.0
  Ti  Ti14  1  0.670  0.240  0.284  1.0
  Ti  Ti15  1  0.330  0.240  0.784  1.0
  O  O16  1  0.468  0.199  0.717  1.0
  O  O17  1  0.034  0.200  0.283  1.0
  O  O18  1  0.966  0.200  0.783  1.0
  O  O19  1  0.532  0.199  0.217  1.0
  O  O20  1  0.608  0.195  0.433  1.0
  O  O21  1  0.892  0.198  0.568  1.0
  O  O22  1  0.108  0.198  0.068  1.0
  O  O23  1  0.392  0.195  0.933  1.0
  O  O24  1  0.822  0.195  0.359  1.0
  O  O25  1  0.683  0.199  0.641  1.0
  O  O26  1  0.178  0.195  0.859  1.0
  O  O27  1  0.317  0.199  0.141  1.0
  O  O28  1  0.406  0.192  0.494  1.0
  O  O29  1  0.095  0.190  0.507  1.0
  O  O30  1  0.905  0.190  0.007  1.0
  O  O31  1  0.594  0.192  0.994  1.0
  O  O32  1  0.754  0.187  0.158  1.0
  O  O33  1  0.745  0.191  0.844  1.0
  O  O34  1  0.246  0.187  0.658  1.0
  O  O35  1  0.255  0.191  0.344  1.0
  O  O36  1  0.749  0.690  0.000  1.0
  O  O37  1  0.251  0.690  0.500  1.0
  O  O38  1  0.672  0.681  0.293  1.0
  O  O39  1  0.829  0.698  0.706  1.0
  O  O40  1  0.171  0.698  0.206  1.0
  O  O41  1  0.328  0.681  0.793  1.0
  O  O42  1  0.959  0.697  0.422  1.0
  O  O43  1  0.544  0.697  0.579  1.0
  O  O44  1  0.041  0.697  0.922  1.0
  O  O45  1  0.456  0.697  0.079  1.0
[/CIF]
.
The material described by Ba3TiTa4O15 crystallizes in the monoclinic Pc space group. There are three inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one O(12), one O(13), one O(14), one O(15), two equivalent O(3), two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms to form BaO12 cuboctahedra that share faces with two equivalent Ba(1)O12 cuboctahedra, faces with two equivalent Ti(1)O6 octahedra, faces with two equivalent Ta(2)O6 octahedra, faces with two equivalent Ta(3)O6 octahedra, and faces with two equivalent Ta(4)O6 octahedra. In the second Ba site, Ba(2) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(10), and two equivalent O(7) atoms. In the third Ba site, Ba(3) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(8), and two equivalent O(9) atoms. Ti(1) is bonded to one O(1), one O(3), one O(5), one O(9), and two equivalent O(12) atoms to form distorted TiO6 octahedra that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(3)O6 octahedra, corners with two equivalent Ti(1)O6 octahedra, corners with two equivalent Ta(4)O6 octahedra, and faces with two equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 7-39°. There are four inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(10), one O(7), one O(8), one O(9), and two equivalent O(11) atoms to form TaO6 octahedra that share  a cornercorner with one Ti(1)O6 octahedra,  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Ta(3)O6 octahedra,  a cornercorner with one Ta(4)O6 octahedra, and corners with two equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-36°. In the second Ta site, Ta(2) is bonded to one O(10), one O(2), one O(4), one O(6), and two equivalent O(13) atoms to form TaO6 octahedra that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(4)O6 octahedra, corners with two equivalent Ta(2)O6 octahedra, corners with two equivalent Ta(3)O6 octahedra, and faces with two equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 3-37°. In the third Ta site, Ta(3) is bonded to one O(2), one O(4), one O(5), one O(8), and two equivalent O(14) atoms to form TaO6 octahedra that share  a cornercorner with one Ti(1)O6 octahedra,  a cornercorner with one Ta(1)O6 octahedra, corners with two equivalent Ta(2)O6 octahedra, corners with two equivalent Ta(3)O6 octahedra, and faces with two equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 1-37°. In the fourth Ta site, Ta(4) is bonded to one O(1), one O(3), one O(6), one O(7), and two equivalent O(15) atoms to form TaO6 octahedra that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(2)O6 octahedra, corners with two equivalent Ti(1)O6 octahedra, corners with two equivalent Ta(4)O6 octahedra, and faces with two equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 3-39°. There are fifteen inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Ba(2), one Ti(1), and one Ta(4) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Ba(3), one Ta(2), and one Ta(3) atom. In the third O site, O(3) is bonded in a distorted linear geometry to two equivalent Ba(1), one Ti(1), and one Ta(4) atom. In the fourth O site, O(4) is bonded in a distorted linear geometry to two equivalent Ba(1), one Ta(2), and one Ta(3) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to two equivalent Ba(1), one Ti(1), and one Ta(3) atom. In the sixth O site, O(6) is bonded in a distorted linear geometry to two equivalent Ba(1), one Ta(2), and one Ta(4) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to two equivalent Ba(2), one Ta(1), and one Ta(4) atom. In the eighth O site, O(8) is bonded in a distorted bent 150 degrees geometry to two equivalent Ba(3), one Ta(1), and one Ta(3) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to two equivalent Ba(3), one Ti(1), and one Ta(1) atom. In the tenth O site, O(10) is bonded in a distorted bent 150 degrees geometry to two equivalent Ba(2), one Ta(1), and one Ta(2) atom. In the eleventh O site, O(11) is bonded in a linear geometry to two equivalent Ta(1) atoms. In the twelfth O site, O(12) is bonded in a 1-coordinate geometry to one Ba(1) and two equivalent Ti(1) atoms. In the thirteenth O site, O(13) is bonded in a distorted linear geometry to one Ba(1) and two equivalent Ta(2) atoms. In the fourteenth O site, O(14) is bonded in a distorted linear geometry to one Ba(1) and two equivalent Ta(3) atoms. In the fifteenth O site, O(15) is bonded in a distorted linear geometry to one Ba(1) and two equivalent Ta(4) atoms. is represented by the CIF file [CIF]
data_Ba3Ta4TiO15
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.760
_cell_length_b   4.019
_cell_length_c   12.685
_cell_angle_alpha   89.952
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   650.420
_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
  Ba  Ba0  1  0.748  0.705  0.494  1.0
  Ba  Ba1  1  0.252  0.705  0.994  1.0
  Ba  Ba2  1  0.573  0.708  0.829  1.0
  Ba  Ba3  1  0.917  0.706  0.174  1.0
  Ba  Ba4  1  0.083  0.706  0.674  1.0
  Ba  Ba5  1  0.427  0.708  0.329  1.0
  Ta  Ta6  1  0.751  0.200  0.004  1.0
  Ta  Ta7  1  0.249  0.200  0.504  1.0
  Ta  Ta8  1  0.824  0.209  0.714  1.0
  Ta  Ta9  1  0.176  0.209  0.214  1.0
  Ta  Ta10  1  0.960  0.208  0.424  1.0
  Ta  Ta11  1  0.536  0.207  0.574  1.0
  Ta  Ta12  1  0.040  0.208  0.924  1.0
  Ta  Ta13  1  0.464  0.207  0.074  1.0
  Ti  Ti14  1  0.670  0.240  0.284  1.0
  Ti  Ti15  1  0.330  0.240  0.784  1.0
  O  O16  1  0.468  0.199  0.717  1.0
  O  O17  1  0.034  0.200  0.283  1.0
  O  O18  1  0.966  0.200  0.783  1.0
  O  O19  1  0.532  0.199  0.217  1.0
  O  O20  1  0.608  0.195  0.433  1.0
  O  O21  1  0.892  0.198  0.568  1.0
  O  O22  1  0.108  0.198  0.068  1.0
  O  O23  1  0.392  0.195  0.933  1.0
  O  O24  1  0.822  0.195  0.359  1.0
  O  O25  1  0.683  0.199  0.641  1.0
  O  O26  1  0.178  0.195  0.859  1.0
  O  O27  1  0.317  0.199  0.141  1.0
  O  O28  1  0.406  0.192  0.494  1.0
  O  O29  1  0.095  0.190  0.507  1.0
  O  O30  1  0.905  0.190  0.007  1.0
  O  O31  1  0.594  0.192  0.994  1.0
  O  O32  1  0.754  0.187  0.158  1.0
  O  O33  1  0.745  0.191  0.844  1.0
  O  O34  1  0.246  0.187  0.658  1.0
  O  O35  1  0.255  0.191  0.344  1.0
  O  O36  1  0.749  0.690  0.000  1.0
  O  O37  1  0.251  0.690  0.500  1.0
  O  O38  1  0.672  0.681  0.293  1.0
  O  O39  1  0.829  0.698  0.706  1.0
  O  O40  1  0.171  0.698  0.206  1.0
  O  O41  1  0.328  0.681  0.793  1.0
  O  O42  1  0.959  0.697  0.422  1.0
  O  O43  1  0.544  0.697  0.579  1.0
  O  O44  1  0.041  0.697  0.922  1.0
  O  O45  1  0.456  0.697  0.079  1.0
[/CIF]
.