The material described by Ba8Nb7O24 crystallizes in the trigonal P3m1 space group. There are eight inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to three equivalent O(1), three equivalent O(2), and six equivalent O(7) atoms to form BaO12 cuboctahedra that share corners with six equivalent Ba(1)O12 cuboctahedra, corners with three equivalent Nb(3)O6 octahedra,  a faceface with one Ba(4)O12 cuboctahedra, faces with three equivalent Ba(6)O12 cuboctahedra,  a faceface with one Nb(5)O6 octahedra, faces with three equivalent Nb(2)O6 octahedra, and faces with three equivalent Nb(6)O6 octahedra. The corner-sharing octahedral tilt angles are 14°. In the second Ba site, Ba(2) is bonded to three equivalent O(4), three equivalent O(5), and six equivalent O(6) atoms to form BaO12 cuboctahedra that share corners with three equivalent Ba(5)O12 cuboctahedra, corners with six equivalent Ba(2)O12 cuboctahedra, faces with three equivalent Ba(8)O12 cuboctahedra,  a faceface with one Nb(1)O6 octahedra,  a faceface with one Nb(5)O6 octahedra, and faces with three equivalent Nb(4)O6 octahedra. In the third Ba site, Ba(3) is bonded in a 12-coordinate geometry to three equivalent O(5), three equivalent O(7), and six equivalent O(2) atoms. In the fourth Ba site, Ba(4) is bonded to three equivalent O(1), three equivalent O(3), and six equivalent O(8) atoms to form BaO12 cuboctahedra that share corners with three equivalent Ba(8)O12 cuboctahedra, corners with six equivalent Ba(4)O12 cuboctahedra, corners with three equivalent Nb(2)O6 octahedra,  a faceface with one Ba(1)O12 cuboctahedra, faces with three equivalent Ba(5)O12 cuboctahedra, faces with three equivalent Ba(6)O12 cuboctahedra,  a faceface with one Nb(1)O6 octahedra, faces with three equivalent Nb(3)O6 octahedra, and faces with three equivalent Nb(7)O6 octahedra. The corner-sharing octahedral tilt angles are 13°. In the fifth Ba site, Ba(5) is bonded to three equivalent O(4), three equivalent O(8), and six equivalent O(3) atoms to form BaO12 cuboctahedra that share corners with three equivalent Ba(2)O12 cuboctahedra, corners with three equivalent Ba(6)O12 cuboctahedra, corners with six equivalent Ba(5)O12 cuboctahedra, faces with three equivalent Ba(4)O12 cuboctahedra, faces with three equivalent Ba(8)O12 cuboctahedra,  a faceface with one Nb(3)O6 octahedra,  a faceface with one Nb(4)O6 octahedra, faces with three equivalent Nb(1)O6 octahedra, and faces with three equivalent Nb(7)O6 octahedra. In the sixth Ba site, Ba(6) is bonded to three equivalent O(7), three equivalent O(8), and six equivalent O(1) atoms to form BaO12 cuboctahedra that share corners with three equivalent Ba(5)O12 cuboctahedra, corners with six equivalent Ba(6)O12 cuboctahedra, faces with three equivalent Ba(1)O12 cuboctahedra, faces with three equivalent Ba(4)O12 cuboctahedra,  a faceface with one Nb(6)O6 octahedra,  a faceface with one Nb(7)O6 octahedra, faces with three equivalent Nb(2)O6 octahedra, and faces with three equivalent Nb(3)O6 octahedra. In the seventh Ba site, Ba(7) is bonded in a 12-coordinate geometry to three equivalent O(2), three equivalent O(6), and six equivalent O(5) atoms. In the eighth Ba site, Ba(8) is bonded to three equivalent O(3), three equivalent O(6), and six equivalent O(4) atoms to form BaO12 cuboctahedra that share corners with three equivalent Ba(4)O12 cuboctahedra, corners with six equivalent Ba(8)O12 cuboctahedra, faces with three equivalent Ba(2)O12 cuboctahedra, faces with three equivalent Ba(5)O12 cuboctahedra,  a faceface with one Nb(7)O6 octahedra, faces with three equivalent Nb(1)O6 octahedra, and faces with three equivalent Nb(4)O6 octahedra. There are seven inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to three equivalent O(3) and three equivalent O(4) atoms to form NbO6 octahedra that share corners with three equivalent Nb(4)O6 octahedra, corners with three equivalent Nb(7)O6 octahedra,  a faceface with one Ba(2)O12 cuboctahedra,  a faceface with one Ba(4)O12 cuboctahedra, faces with three equivalent Ba(5)O12 cuboctahedra, and faces with three equivalent Ba(8)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 2-7°. In the second Nb site, Nb(2) is bonded to three equivalent O(1) and three equivalent O(7) atoms to form NbO6 octahedra that share corners with three equivalent Ba(4)O12 cuboctahedra, corners with three equivalent Nb(6)O6 octahedra, faces with three equivalent Ba(1)O12 cuboctahedra, faces with three equivalent Ba(6)O12 cuboctahedra, and  a faceface with one Nb(3)O6 octahedra. The corner-sharing octahedral tilt angles are 6°. In the third Nb site, Nb(3) is bonded to three equivalent O(1) and three equivalent O(8) atoms to form NbO6 octahedra that share corners with three equivalent Ba(1)O12 cuboctahedra, corners with three equivalent Nb(7)O6 octahedra,  a faceface with one Ba(5)O12 cuboctahedra, faces with three equivalent Ba(4)O12 cuboctahedra, faces with three equivalent Ba(6)O12 cuboctahedra, and  a faceface with one Nb(2)O6 octahedra. The corner-sharing octahedral tilt angles are 2°. In the fourth Nb site, Nb(4) is bonded to three equivalent O(4) and three equivalent O(6) atoms to form distorted NbO6 octahedra that share corners with three equivalent Nb(1)O6 octahedra,  a faceface with one Ba(5)O12 cuboctahedra, faces with three equivalent Ba(2)O12 cuboctahedra, and faces with three equivalent Ba(8)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 7°. In the fifth Nb site, Nb(5) is bonded to three equivalent O(2) and three equivalent O(5) atoms to form NbO6 octahedra that share corners with three equivalent Nb(6)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 are 9°. In the sixth Nb site, Nb(6) is bonded to three equivalent O(2) and three equivalent O(7) atoms to form NbO6 octahedra that share corners with three equivalent Nb(2)O6 octahedra, corners with three equivalent Nb(5)O6 octahedra,  a faceface with one Ba(6)O12 cuboctahedra, and faces with three equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 6-9°. In the seventh Nb site, Nb(7) is bonded to three equivalent O(3) and three equivalent O(8) atoms to form NbO6 octahedra that share corners with three equivalent Nb(1)O6 octahedra, corners with three equivalent Nb(3)O6 octahedra,  a faceface with one Ba(6)O12 cuboctahedra,  a faceface with one Ba(8)O12 cuboctahedra, faces with three equivalent Ba(4)O12 cuboctahedra, and faces with three equivalent Ba(5)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 2°. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Ba(1), one Ba(4), two equivalent Ba(6), one Nb(2), and one Nb(3) atom to form a mixture of distorted face and corner-sharing OBa4Nb2 octahedra. The corner-sharing octahedral tilt angles range from 2-60°. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Ba(1), one Ba(7), two equivalent Ba(3), one Nb(5), and one Nb(6) atom. In the third O site, O(3) is bonded in a distorted linear geometry to one Ba(4), one Ba(8), two equivalent Ba(5), one Nb(1), and one Nb(7) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Ba(2), one Ba(5), two equivalent Ba(8), one Nb(1), and one Nb(4) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one Ba(2), one Ba(3), two equivalent Ba(7), and one Nb(5) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Ba(7), one Ba(8), two equivalent Ba(2), and one Nb(4) atom. In the seventh O site, O(7) is bonded in a distorted linear geometry to one Ba(3), one Ba(6), two equivalent Ba(1), one Nb(2), and one Nb(6) atom. In the eighth O site, O(8) is bonded in a distorted linear geometry to one Ba(5), one Ba(6), two equivalent Ba(4), one Nb(3), and one Nb(7) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ba8Nb7O24
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.935
_cell_length_b   5.935
_cell_length_c   19.234
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   586.713
_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  0.667  0.333  0.132  1.0
  Ba  Ba1  1  0.667  0.333  0.755  1.0
  Ba  Ba2  1  0.333  0.667  0.986  1.0
  Ba  Ba3  1  0.667  0.333  0.366  1.0
  Ba  Ba4  1  0.333  0.667  0.504  1.0
  Ba  Ba5  1  0.000  0.000  0.249  1.0
  Ba  Ba6  1  0.000  0.000  0.855  1.0
  Ba  Ba7  1  0.000  0.000  0.632  1.0
  Nb  Nb8  1  0.667  0.333  0.563  1.0
  Nb  Nb9  1  0.333  0.667  0.183  1.0
  Nb  Nb10  1  0.333  0.667  0.318  1.0
  Nb  Nb11  1  0.333  0.667  0.697  1.0
  Nb  Nb12  1  0.667  0.333  0.934  1.0
  Nb  Nb13  1  0.000  0.000  0.059  1.0
  Nb  Nb14  1  0.000  0.000  0.439  1.0
  O  O15  1  0.495  0.505  0.250  1.0
  O  O16  1  0.328  0.164  0.008  1.0
  O  O17  1  0.335  0.167  0.499  1.0
  O  O18  1  0.503  0.497  0.621  1.0
  O  O19  1  0.510  0.490  0.883  1.0
  O  O20  1  0.503  0.007  0.621  1.0
  O  O21  1  0.510  0.020  0.883  1.0
  O  O22  1  0.495  0.989  0.250  1.0
  O  O23  1  0.661  0.830  0.741  1.0
  O  O24  1  0.993  0.497  0.621  1.0
  O  O25  1  0.980  0.490  0.883  1.0
  O  O26  1  0.836  0.164  0.008  1.0
  O  O27  1  0.833  0.167  0.499  1.0
  O  O28  1  0.673  0.836  0.127  1.0
  O  O29  1  0.672  0.836  0.377  1.0
  O  O30  1  0.011  0.505  0.250  1.0
  O  O31  1  0.164  0.328  0.377  1.0
  O  O32  1  0.836  0.672  0.008  1.0
  O  O33  1  0.833  0.665  0.499  1.0
  O  O34  1  0.164  0.327  0.127  1.0
  O  O35  1  0.170  0.339  0.741  1.0
  O  O36  1  0.164  0.836  0.127  1.0
  O  O37  1  0.164  0.836  0.377  1.0
  O  O38  1  0.170  0.830  0.741  1.0
[/CIF]
.
The material described by Ba8Nb7O24 crystallizes in the trigonal P3m1 space group. There are eight inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to three equivalent O(1), three equivalent O(2), and six equivalent O(7) atoms to form BaO12 cuboctahedra that share corners with six equivalent Ba(1)O12 cuboctahedra, corners with three equivalent Nb(3)O6 octahedra,  a faceface with one Ba(4)O12 cuboctahedra, faces with three equivalent Ba(6)O12 cuboctahedra,  a faceface with one Nb(5)O6 octahedra, faces with three equivalent Nb(2)O6 octahedra, and faces with three equivalent Nb(6)O6 octahedra. The corner-sharing octahedral tilt angles are 14°. In the second Ba site, Ba(2) is bonded to three equivalent O(4), three equivalent O(5), and six equivalent O(6) atoms to form BaO12 cuboctahedra that share corners with three equivalent Ba(5)O12 cuboctahedra, corners with six equivalent Ba(2)O12 cuboctahedra, faces with three equivalent Ba(8)O12 cuboctahedra,  a faceface with one Nb(1)O6 octahedra,  a faceface with one Nb(5)O6 octahedra, and faces with three equivalent Nb(4)O6 octahedra. In the third Ba site, Ba(3) is bonded in a 12-coordinate geometry to three equivalent O(5), three equivalent O(7), and six equivalent O(2) atoms. In the fourth Ba site, Ba(4) is bonded to three equivalent O(1), three equivalent O(3), and six equivalent O(8) atoms to form BaO12 cuboctahedra that share corners with three equivalent Ba(8)O12 cuboctahedra, corners with six equivalent Ba(4)O12 cuboctahedra, corners with three equivalent Nb(2)O6 octahedra,  a faceface with one Ba(1)O12 cuboctahedra, faces with three equivalent Ba(5)O12 cuboctahedra, faces with three equivalent Ba(6)O12 cuboctahedra,  a faceface with one Nb(1)O6 octahedra, faces with three equivalent Nb(3)O6 octahedra, and faces with three equivalent Nb(7)O6 octahedra. The corner-sharing octahedral tilt angles are 13°. In the fifth Ba site, Ba(5) is bonded to three equivalent O(4), three equivalent O(8), and six equivalent O(3) atoms to form BaO12 cuboctahedra that share corners with three equivalent Ba(2)O12 cuboctahedra, corners with three equivalent Ba(6)O12 cuboctahedra, corners with six equivalent Ba(5)O12 cuboctahedra, faces with three equivalent Ba(4)O12 cuboctahedra, faces with three equivalent Ba(8)O12 cuboctahedra,  a faceface with one Nb(3)O6 octahedra,  a faceface with one Nb(4)O6 octahedra, faces with three equivalent Nb(1)O6 octahedra, and faces with three equivalent Nb(7)O6 octahedra. In the sixth Ba site, Ba(6) is bonded to three equivalent O(7), three equivalent O(8), and six equivalent O(1) atoms to form BaO12 cuboctahedra that share corners with three equivalent Ba(5)O12 cuboctahedra, corners with six equivalent Ba(6)O12 cuboctahedra, faces with three equivalent Ba(1)O12 cuboctahedra, faces with three equivalent Ba(4)O12 cuboctahedra,  a faceface with one Nb(6)O6 octahedra,  a faceface with one Nb(7)O6 octahedra, faces with three equivalent Nb(2)O6 octahedra, and faces with three equivalent Nb(3)O6 octahedra. In the seventh Ba site, Ba(7) is bonded in a 12-coordinate geometry to three equivalent O(2), three equivalent O(6), and six equivalent O(5) atoms. In the eighth Ba site, Ba(8) is bonded to three equivalent O(3), three equivalent O(6), and six equivalent O(4) atoms to form BaO12 cuboctahedra that share corners with three equivalent Ba(4)O12 cuboctahedra, corners with six equivalent Ba(8)O12 cuboctahedra, faces with three equivalent Ba(2)O12 cuboctahedra, faces with three equivalent Ba(5)O12 cuboctahedra,  a faceface with one Nb(7)O6 octahedra, faces with three equivalent Nb(1)O6 octahedra, and faces with three equivalent Nb(4)O6 octahedra. There are seven inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to three equivalent O(3) and three equivalent O(4) atoms to form NbO6 octahedra that share corners with three equivalent Nb(4)O6 octahedra, corners with three equivalent Nb(7)O6 octahedra,  a faceface with one Ba(2)O12 cuboctahedra,  a faceface with one Ba(4)O12 cuboctahedra, faces with three equivalent Ba(5)O12 cuboctahedra, and faces with three equivalent Ba(8)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 2-7°. In the second Nb site, Nb(2) is bonded to three equivalent O(1) and three equivalent O(7) atoms to form NbO6 octahedra that share corners with three equivalent Ba(4)O12 cuboctahedra, corners with three equivalent Nb(6)O6 octahedra, faces with three equivalent Ba(1)O12 cuboctahedra, faces with three equivalent Ba(6)O12 cuboctahedra, and  a faceface with one Nb(3)O6 octahedra. The corner-sharing octahedral tilt angles are 6°. In the third Nb site, Nb(3) is bonded to three equivalent O(1) and three equivalent O(8) atoms to form NbO6 octahedra that share corners with three equivalent Ba(1)O12 cuboctahedra, corners with three equivalent Nb(7)O6 octahedra,  a faceface with one Ba(5)O12 cuboctahedra, faces with three equivalent Ba(4)O12 cuboctahedra, faces with three equivalent Ba(6)O12 cuboctahedra, and  a faceface with one Nb(2)O6 octahedra. The corner-sharing octahedral tilt angles are 2°. In the fourth Nb site, Nb(4) is bonded to three equivalent O(4) and three equivalent O(6) atoms to form distorted NbO6 octahedra that share corners with three equivalent Nb(1)O6 octahedra,  a faceface with one Ba(5)O12 cuboctahedra, faces with three equivalent Ba(2)O12 cuboctahedra, and faces with three equivalent Ba(8)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 7°. In the fifth Nb site, Nb(5) is bonded to three equivalent O(2) and three equivalent O(5) atoms to form NbO6 octahedra that share corners with three equivalent Nb(6)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 are 9°. In the sixth Nb site, Nb(6) is bonded to three equivalent O(2) and three equivalent O(7) atoms to form NbO6 octahedra that share corners with three equivalent Nb(2)O6 octahedra, corners with three equivalent Nb(5)O6 octahedra,  a faceface with one Ba(6)O12 cuboctahedra, and faces with three equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 6-9°. In the seventh Nb site, Nb(7) is bonded to three equivalent O(3) and three equivalent O(8) atoms to form NbO6 octahedra that share corners with three equivalent Nb(1)O6 octahedra, corners with three equivalent Nb(3)O6 octahedra,  a faceface with one Ba(6)O12 cuboctahedra,  a faceface with one Ba(8)O12 cuboctahedra, faces with three equivalent Ba(4)O12 cuboctahedra, and faces with three equivalent Ba(5)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 2°. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Ba(1), one Ba(4), two equivalent Ba(6), one Nb(2), and one Nb(3) atom to form a mixture of distorted face and corner-sharing OBa4Nb2 octahedra. The corner-sharing octahedral tilt angles range from 2-60°. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Ba(1), one Ba(7), two equivalent Ba(3), one Nb(5), and one Nb(6) atom. In the third O site, O(3) is bonded in a distorted linear geometry to one Ba(4), one Ba(8), two equivalent Ba(5), one Nb(1), and one Nb(7) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Ba(2), one Ba(5), two equivalent Ba(8), one Nb(1), and one Nb(4) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one Ba(2), one Ba(3), two equivalent Ba(7), and one Nb(5) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Ba(7), one Ba(8), two equivalent Ba(2), and one Nb(4) atom. In the seventh O site, O(7) is bonded in a distorted linear geometry to one Ba(3), one Ba(6), two equivalent Ba(1), one Nb(2), and one Nb(6) atom. In the eighth O site, O(8) is bonded in a distorted linear geometry to one Ba(5), one Ba(6), two equivalent Ba(4), one Nb(3), and one Nb(7) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ba8Nb7O24
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.935
_cell_length_b   5.935
_cell_length_c   19.234
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   586.713
_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  0.667  0.333  0.132  1.0
  Ba  Ba1  1  0.667  0.333  0.755  1.0
  Ba  Ba2  1  0.333  0.667  0.986  1.0
  Ba  Ba3  1  0.667  0.333  0.366  1.0
  Ba  Ba4  1  0.333  0.667  0.504  1.0
  Ba  Ba5  1  0.000  0.000  0.249  1.0
  Ba  Ba6  1  0.000  0.000  0.855  1.0
  Ba  Ba7  1  0.000  0.000  0.632  1.0
  Nb  Nb8  1  0.667  0.333  0.563  1.0
  Nb  Nb9  1  0.333  0.667  0.183  1.0
  Nb  Nb10  1  0.333  0.667  0.318  1.0
  Nb  Nb11  1  0.333  0.667  0.697  1.0
  Nb  Nb12  1  0.667  0.333  0.934  1.0
  Nb  Nb13  1  0.000  0.000  0.059  1.0
  Nb  Nb14  1  0.000  0.000  0.439  1.0
  O  O15  1  0.495  0.505  0.250  1.0
  O  O16  1  0.328  0.164  0.008  1.0
  O  O17  1  0.335  0.167  0.499  1.0
  O  O18  1  0.503  0.497  0.621  1.0
  O  O19  1  0.510  0.490  0.883  1.0
  O  O20  1  0.503  0.007  0.621  1.0
  O  O21  1  0.510  0.020  0.883  1.0
  O  O22  1  0.495  0.989  0.250  1.0
  O  O23  1  0.661  0.830  0.741  1.0
  O  O24  1  0.993  0.497  0.621  1.0
  O  O25  1  0.980  0.490  0.883  1.0
  O  O26  1  0.836  0.164  0.008  1.0
  O  O27  1  0.833  0.167  0.499  1.0
  O  O28  1  0.673  0.836  0.127  1.0
  O  O29  1  0.672  0.836  0.377  1.0
  O  O30  1  0.011  0.505  0.250  1.0
  O  O31  1  0.164  0.328  0.377  1.0
  O  O32  1  0.836  0.672  0.008  1.0
  O  O33  1  0.833  0.665  0.499  1.0
  O  O34  1  0.164  0.327  0.127  1.0
  O  O35  1  0.170  0.339  0.741  1.0
  O  O36  1  0.164  0.836  0.127  1.0
  O  O37  1  0.164  0.836  0.377  1.0
  O  O38  1  0.170  0.830  0.741  1.0
[/CIF]
.