The compound described by BaTa6O16 crystallizes in the orthorhombic Amm2 space group. Ba(1) is bonded in a 9-coordinate geometry to one O(10), two equivalent O(4), two equivalent O(7), and four equivalent O(1) atoms. There are four inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(6), two equivalent O(2), two equivalent O(3), and two equivalent O(9) atoms to form TaO7 pentagonal bipyramids that share corners with two equivalent Ta(1)O7 pentagonal bipyramids,  an edgeedge with one Ta(3)O6 octahedra, edges with two equivalent Ta(2)O6 octahedra, and edges with two equivalent Ta(4)O6 octahedra. In the second Ta site, Ta(2) is bonded to one O(1), one O(2), one O(5), one O(6), and two equivalent O(8) atoms to form TaO6 octahedra that share  a cornercorner with one Ta(3)O6 octahedra, corners with two equivalent Ta(4)O6 octahedra, corners with three equivalent Ta(2)O6 octahedra, and  an edgeedge with one Ta(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 5-44°. In the third Ta site, Ta(3) is bonded to two equivalent O(1), two equivalent O(10), and two equivalent O(3) atoms to form TaO6 octahedra that share corners with two equivalent Ta(2)O6 octahedra, corners with two equivalent Ta(3)O6 octahedra, corners with two equivalent Ta(4)O6 octahedra, and  an edgeedge with one Ta(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 8-44°. In the fourth Ta site, Ta(4) is bonded to one O(2), one O(3), one O(4), one O(5), and two equivalent O(7) atoms to form TaO6 octahedra that share  a cornercorner with one Ta(3)O6 octahedra, corners with two equivalent Ta(2)O6 octahedra, corners with three equivalent Ta(4)O6 octahedra, and  an edgeedge with one Ta(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 17-38°. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ba(1), one Ta(2), and one Ta(3) atom. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Ta(1), one Ta(2), and one Ta(4) atom. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Ta(1), one Ta(3), and one Ta(4) atom. In the fourth O site, O(4) is bonded to two equivalent Ba(1) and two equivalent Ta(4) atoms to form distorted corner-sharing OBa2Ta2 trigonal pyramids. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Ta(2) and one Ta(4) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Ta(1) and two equivalent Ta(2) atoms. In the seventh O site, O(7) is bonded in a distorted linear geometry to one Ba(1) and two equivalent Ta(4) atoms. In the eighth O site, O(8) is bonded in a linear geometry to two equivalent Ta(2) atoms. In the ninth O site, O(9) is bonded in a linear geometry to two equivalent Ta(1) atoms. In the tenth O site, O(10) is bonded in a distorted linear geometry to one Ba(1) and two equivalent Ta(3) atoms. is represented by the CIF file [CIF]
data_BaTa6O16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.163
_cell_length_b   9.163
_cell_length_c   3.888
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   111.657
_symmetry_Int_Tables_number   1
_cell_volume   303.359
_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
  Ba  Ba0  1  0.601  0.399  0.500  1.0
  Ta  Ta1  1  0.009  0.991  0.000  1.0
  Ta  Ta2  1  0.371  0.999  0.000  1.0
  Ta  Ta3  1  0.796  0.204  0.000  1.0
  Ta  Ta4  1  0.248  0.380  0.000  1.0
  Ta  Ta5  1  0.001  0.629  0.000  1.0
  Ta  Ta6  1  0.620  0.752  0.000  1.0
  O  O7  1  0.569  0.176  0.000  1.0
  O  O8  1  0.247  0.150  0.000  1.0
  O  O9  1  0.018  0.227  0.000  1.0
  O  O10  1  0.824  0.431  0.000  1.0
  O  O11  1  0.478  0.522  0.000  1.0
  O  O12  1  0.162  0.538  0.000  1.0
  O  O13  1  0.850  0.753  0.000  1.0
  O  O14  1  0.462  0.838  0.000  1.0
  O  O15  1  0.144  0.856  0.000  1.0
  O  O16  1  0.773  0.982  0.000  1.0
  O  O17  1  0.275  0.371  0.500  1.0
  O  O18  1  0.372  0.009  0.500  1.0
  O  O19  1  0.004  0.996  0.500  1.0
  O  O20  1  0.787  0.213  0.500  1.0
  O  O21  1  0.991  0.628  0.500  1.0
  O  O22  1  0.629  0.725  0.500  1.0
[/CIF]
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The compound described by BaTa6O16 crystallizes in the orthorhombic Amm2 space group. Ba(1) is bonded in a 9-coordinate geometry to one O(10), two equivalent O(4), two equivalent O(7), and four equivalent O(1) atoms. There are four inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(6), two equivalent O(2), two equivalent O(3), and two equivalent O(9) atoms to form TaO7 pentagonal bipyramids that share corners with two equivalent Ta(1)O7 pentagonal bipyramids,  an edgeedge with one Ta(3)O6 octahedra, edges with two equivalent Ta(2)O6 octahedra, and edges with two equivalent Ta(4)O6 octahedra. In the second Ta site, Ta(2) is bonded to one O(1), one O(2), one O(5), one O(6), and two equivalent O(8) atoms to form TaO6 octahedra that share  a cornercorner with one Ta(3)O6 octahedra, corners with two equivalent Ta(4)O6 octahedra, corners with three equivalent Ta(2)O6 octahedra, and  an edgeedge with one Ta(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 5-44°. In the third Ta site, Ta(3) is bonded to two equivalent O(1), two equivalent O(10), and two equivalent O(3) atoms to form TaO6 octahedra that share corners with two equivalent Ta(2)O6 octahedra, corners with two equivalent Ta(3)O6 octahedra, corners with two equivalent Ta(4)O6 octahedra, and  an edgeedge with one Ta(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 8-44°. In the fourth Ta site, Ta(4) is bonded to one O(2), one O(3), one O(4), one O(5), and two equivalent O(7) atoms to form TaO6 octahedra that share  a cornercorner with one Ta(3)O6 octahedra, corners with two equivalent Ta(2)O6 octahedra, corners with three equivalent Ta(4)O6 octahedra, and  an edgeedge with one Ta(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 17-38°. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ba(1), one Ta(2), and one Ta(3) atom. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Ta(1), one Ta(2), and one Ta(4) atom. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Ta(1), one Ta(3), and one Ta(4) atom. In the fourth O site, O(4) is bonded to two equivalent Ba(1) and two equivalent Ta(4) atoms to form distorted corner-sharing OBa2Ta2 trigonal pyramids. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Ta(2) and one Ta(4) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Ta(1) and two equivalent Ta(2) atoms. In the seventh O site, O(7) is bonded in a distorted linear geometry to one Ba(1) and two equivalent Ta(4) atoms. In the eighth O site, O(8) is bonded in a linear geometry to two equivalent Ta(2) atoms. In the ninth O site, O(9) is bonded in a linear geometry to two equivalent Ta(1) atoms. In the tenth O site, O(10) is bonded in a distorted linear geometry to one Ba(1) and two equivalent Ta(3) atoms. is represented by the CIF file [CIF]
data_BaTa6O16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.163
_cell_length_b   9.163
_cell_length_c   3.888
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   111.657
_symmetry_Int_Tables_number   1
_cell_volume   303.359
_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
  Ba  Ba0  1  0.601  0.399  0.500  1.0
  Ta  Ta1  1  0.009  0.991  0.000  1.0
  Ta  Ta2  1  0.371  0.999  0.000  1.0
  Ta  Ta3  1  0.796  0.204  0.000  1.0
  Ta  Ta4  1  0.248  0.380  0.000  1.0
  Ta  Ta5  1  0.001  0.629  0.000  1.0
  Ta  Ta6  1  0.620  0.752  0.000  1.0
  O  O7  1  0.569  0.176  0.000  1.0
  O  O8  1  0.247  0.150  0.000  1.0
  O  O9  1  0.018  0.227  0.000  1.0
  O  O10  1  0.824  0.431  0.000  1.0
  O  O11  1  0.478  0.522  0.000  1.0
  O  O12  1  0.162  0.538  0.000  1.0
  O  O13  1  0.850  0.753  0.000  1.0
  O  O14  1  0.462  0.838  0.000  1.0
  O  O15  1  0.144  0.856  0.000  1.0
  O  O16  1  0.773  0.982  0.000  1.0
  O  O17  1  0.275  0.371  0.500  1.0
  O  O18  1  0.372  0.009  0.500  1.0
  O  O19  1  0.004  0.996  0.500  1.0
  O  O20  1  0.787  0.213  0.500  1.0
  O  O21  1  0.991  0.628  0.500  1.0
  O  O22  1  0.629  0.725  0.500  1.0
[/CIF]
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