The compound described by Ba4La2Ti3Nb2O18 crystallizes in the trigonal R-3m space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to three equivalent O(1) and nine equivalent O(3) atoms to form BaO12 cuboctahedra that share corners with three equivalent La(1)O12 cuboctahedra, corners with six equivalent Ba(1)O12 cuboctahedra, faces with three equivalent Ba(1)O12 cuboctahedra, faces with three equivalent La(1)O12 cuboctahedra,  a faceface with one Nb(1)O6 octahedra, faces with three equivalent Ti(2)O6 octahedra, and faces with four equivalent Ti(1)O6 octahedra. In the second Ba site, Ba(2) is bonded in a 12-coordinate geometry to three equivalent O(1) and nine equivalent O(2) atoms. La(1) is bonded to three equivalent O(2), three equivalent O(3), and six equivalent O(1) atoms to form LaO12 cuboctahedra that share corners with three equivalent Ba(1)O12 cuboctahedra, corners with six equivalent La(1)O12 cuboctahedra, faces with three equivalent Ba(1)O12 cuboctahedra,  a faceface with one Ti(2)O6 octahedra, faces with three equivalent Ti(1)O6 octahedra, and faces with three equivalent Nb(1)O6 octahedra. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to three equivalent O(1) and three equivalent O(3) atoms to form TiO6 octahedra that share corners with three equivalent Ti(2)O6 octahedra, corners with three equivalent Nb(1)O6 octahedra, faces with three equivalent La(1)O12 cuboctahedra, and faces with four equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 2-6°. In the second Ti site, Ti(2) is bonded to six equivalent O(3) atoms to form TiO6 octahedra that share corners with six equivalent Ti(1)O6 octahedra, faces with two equivalent La(1)O12 cuboctahedra, and faces with six equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 2°. Nb(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form NbO6 octahedra that share corners with three equivalent Ti(1)O6 octahedra,  a faceface with one Ba(1)O12 cuboctahedra, and faces with three equivalent La(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 6°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Ba(1), one Ba(2), two equivalent La(1), one Ti(1), and one Nb(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to three equivalent Ba(2), one La(1), and one Nb(1) atom. In the third O site, O(3) is bonded in a distorted linear geometry to three equivalent Ba(1), one La(1), one Ti(1), and one Ti(2) atom. is represented by the CIF file [CIF]
data_Ba4La2Ti3Nb2O18
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   14.450
_cell_length_b   14.450
_cell_length_c   14.450
_cell_angle_alpha   22.859
_cell_angle_beta   22.859
_cell_angle_gamma   22.859
_symmetry_Int_Tables_number   1
_cell_volume   399.560
_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  0.140  0.140  0.140  1.0
  Ba  Ba1  1  0.312  0.312  0.312  1.0
  Ba  Ba2  1  0.688  0.688  0.688  1.0
  Ba  Ba3  1  0.860  0.860  0.860  1.0
  La  La4  1  0.415  0.415  0.415  1.0
  La  La5  1  0.585  0.585  0.585  1.0
  Ti  Ti6  1  0.222  0.222  0.222  1.0
  Ti  Ti7  1  0.500  0.500  0.500  1.0
  Ti  Ti8  1  0.778  0.778  0.778  1.0
  Nb  Nb9  1  0.054  0.054  0.054  1.0
  Nb  Nb10  1  0.946  0.946  0.946  1.0
  O  O11  1  0.083  0.083  0.576  1.0
  O  O12  1  0.576  0.083  0.083  1.0
  O  O13  1  0.083  0.576  0.083  1.0
  O  O14  1  0.690  0.206  0.206  1.0
  O  O15  1  0.206  0.206  0.690  1.0
  O  O16  1  0.206  0.690  0.206  1.0
  O  O17  1  0.635  0.145  0.635  1.0
  O  O18  1  0.145  0.635  0.635  1.0
  O  O19  1  0.635  0.635  0.145  1.0
  O  O20  1  0.855  0.365  0.365  1.0
  O  O21  1  0.365  0.365  0.855  1.0
  O  O22  1  0.365  0.855  0.365  1.0
  O  O23  1  0.794  0.310  0.794  1.0
  O  O24  1  0.310  0.794  0.794  1.0
  O  O25  1  0.794  0.794  0.310  1.0
  O  O26  1  0.917  0.424  0.917  1.0
  O  O27  1  0.917  0.917  0.424  1.0
  O  O28  1  0.424  0.917  0.917  1.0
[/CIF]
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The compound described by Ba4La2Ti3Nb2O18 crystallizes in the trigonal R-3m space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to three equivalent O(1) and nine equivalent O(3) atoms to form BaO12 cuboctahedra that share corners with three equivalent La(1)O12 cuboctahedra, corners with six equivalent Ba(1)O12 cuboctahedra, faces with three equivalent Ba(1)O12 cuboctahedra, faces with three equivalent La(1)O12 cuboctahedra,  a faceface with one Nb(1)O6 octahedra, faces with three equivalent Ti(2)O6 octahedra, and faces with four equivalent Ti(1)O6 octahedra. In the second Ba site, Ba(2) is bonded in a 12-coordinate geometry to three equivalent O(1) and nine equivalent O(2) atoms. La(1) is bonded to three equivalent O(2), three equivalent O(3), and six equivalent O(1) atoms to form LaO12 cuboctahedra that share corners with three equivalent Ba(1)O12 cuboctahedra, corners with six equivalent La(1)O12 cuboctahedra, faces with three equivalent Ba(1)O12 cuboctahedra,  a faceface with one Ti(2)O6 octahedra, faces with three equivalent Ti(1)O6 octahedra, and faces with three equivalent Nb(1)O6 octahedra. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to three equivalent O(1) and three equivalent O(3) atoms to form TiO6 octahedra that share corners with three equivalent Ti(2)O6 octahedra, corners with three equivalent Nb(1)O6 octahedra, faces with three equivalent La(1)O12 cuboctahedra, and faces with four equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 2-6°. In the second Ti site, Ti(2) is bonded to six equivalent O(3) atoms to form TiO6 octahedra that share corners with six equivalent Ti(1)O6 octahedra, faces with two equivalent La(1)O12 cuboctahedra, and faces with six equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 2°. Nb(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form NbO6 octahedra that share corners with three equivalent Ti(1)O6 octahedra,  a faceface with one Ba(1)O12 cuboctahedra, and faces with three equivalent La(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 6°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Ba(1), one Ba(2), two equivalent La(1), one Ti(1), and one Nb(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to three equivalent Ba(2), one La(1), and one Nb(1) atom. In the third O site, O(3) is bonded in a distorted linear geometry to three equivalent Ba(1), one La(1), one Ti(1), and one Ti(2) atom. is represented by the CIF file [CIF]
data_Ba4La2Ti3Nb2O18
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   14.450
_cell_length_b   14.450
_cell_length_c   14.450
_cell_angle_alpha   22.859
_cell_angle_beta   22.859
_cell_angle_gamma   22.859
_symmetry_Int_Tables_number   1
_cell_volume   399.560
_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  0.140  0.140  0.140  1.0
  Ba  Ba1  1  0.312  0.312  0.312  1.0
  Ba  Ba2  1  0.688  0.688  0.688  1.0
  Ba  Ba3  1  0.860  0.860  0.860  1.0
  La  La4  1  0.415  0.415  0.415  1.0
  La  La5  1  0.585  0.585  0.585  1.0
  Ti  Ti6  1  0.222  0.222  0.222  1.0
  Ti  Ti7  1  0.500  0.500  0.500  1.0
  Ti  Ti8  1  0.778  0.778  0.778  1.0
  Nb  Nb9  1  0.054  0.054  0.054  1.0
  Nb  Nb10  1  0.946  0.946  0.946  1.0
  O  O11  1  0.083  0.083  0.576  1.0
  O  O12  1  0.576  0.083  0.083  1.0
  O  O13  1  0.083  0.576  0.083  1.0
  O  O14  1  0.690  0.206  0.206  1.0
  O  O15  1  0.206  0.206  0.690  1.0
  O  O16  1  0.206  0.690  0.206  1.0
  O  O17  1  0.635  0.145  0.635  1.0
  O  O18  1  0.145  0.635  0.635  1.0
  O  O19  1  0.635  0.635  0.145  1.0
  O  O20  1  0.855  0.365  0.365  1.0
  O  O21  1  0.365  0.365  0.855  1.0
  O  O22  1  0.365  0.855  0.365  1.0
  O  O23  1  0.794  0.310  0.794  1.0
  O  O24  1  0.310  0.794  0.794  1.0
  O  O25  1  0.794  0.794  0.310  1.0
  O  O26  1  0.917  0.424  0.917  1.0
  O  O27  1  0.917  0.917  0.424  1.0
  O  O28  1  0.424  0.917  0.917  1.0
[/CIF]
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