The compound described by BaNb4PbBi4O18 crystallizes in the orthorhombic Amm2 space group. Ba(1) is bonded to two equivalent O(1), two equivalent O(2), four equivalent O(3), and four equivalent O(5) atoms to form BaO12 cuboctahedra that share corners with four equivalent Ba(1)O12 cuboctahedra, faces with four equivalent Nb(1)O6 octahedra, and faces with four equivalent Nb(2)O6 octahedra. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(1), one O(6), two equivalent O(3), and two equivalent O(5) atoms to form NbO6 octahedra that share  a cornercorner with one Nb(1)O6 octahedra, corners with four equivalent Nb(2)O6 octahedra, and faces with two equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 6-19°. In the second Nb site, Nb(2) is bonded to one O(2), one O(7), two equivalent O(3), and two equivalent O(5) atoms to form NbO6 octahedra that share  a cornercorner with one Nb(2)O6 octahedra, corners with four equivalent Nb(1)O6 octahedra, and faces with two equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 3-19°. Pb(1) is bonded in a 5-coordinate geometry to one O(2) and four equivalent O(5) atoms. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a distorted pentagonal planar geometry to one O(6) and four equivalent O(4) atoms. In the second Bi site, Bi(2) is bonded in a distorted pentagonal planar geometry to one O(7) and four equivalent O(4) atoms. There are seven inequivalent O sites. In the first O site, O(6) is bonded in a distorted bent 120 degrees geometry to one Nb(1) and one Bi(1) atom. In the second O site, O(7) is bonded in a distorted bent 120 degrees geometry to one Nb(2) and one Bi(2) atom. In the third O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Ba(1) and two equivalent Nb(1) atoms. In the fourth O site, O(2) is bonded to two equivalent Ba(1), two equivalent Nb(2), and one Pb(1) atom to form distorted corner-sharing OBa2Nb2Pb square pyramids. In the fifth O site, O(3) is bonded in a distorted linear geometry to one Ba(1), one Nb(1), and one Nb(2) atom. In the sixth O site, O(4) is bonded to two equivalent Bi(1) and two equivalent Bi(2) atoms to form a mixture of corner and edge-sharing OBi4 tetrahedra. In the seventh O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to one Ba(1), one Nb(1), one Nb(2), and one Pb(1) atom. is represented by the CIF file [CIF]
data_BaNb4Bi4PbO18
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.823
_cell_length_b   12.823
_cell_length_c   5.668
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   154.402
_symmetry_Int_Tables_number   1
_cell_volume   402.661
_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  0.242  0.242  0.500  1.0
  Nb  Nb1  1  0.824  0.650  0.500  1.0
  Nb  Nb2  1  0.326  0.150  0.000  1.0
  Nb  Nb3  1  0.150  0.326  0.000  1.0
  Nb  Nb4  1  0.650  0.824  0.500  1.0
  Bi  Bi5  1  0.491  0.086  0.500  1.0
  Bi  Bi6  1  0.903  0.501  0.000  1.0
  Bi  Bi7  1  0.501  0.903  0.000  1.0
  Bi  Bi8  1  0.086  0.491  0.500  1.0
  Pb  Pb9  1  0.711  0.711  0.000  1.0
  O  O10  1  0.773  0.773  0.500  1.0
  O  O11  1  0.248  0.248  0.000  1.0
  O  O12  1  0.098  0.924  0.255  1.0
  O  O13  1  0.098  0.924  0.745  1.0
  O  O14  1  0.924  0.098  0.255  1.0
  O  O15  1  0.924  0.098  0.745  1.0
  O  O16  1  0.247  0.753  0.250  1.0
  O  O17  1  0.247  0.753  0.750  1.0
  O  O18  1  0.753  0.247  0.250  1.0
  O  O19  1  0.753  0.247  0.750  1.0
  O  O20  1  0.437  0.586  0.245  1.0
  O  O21  1  0.437  0.586  0.755  1.0
  O  O22  1  0.586  0.437  0.245  1.0
  O  O23  1  0.586  0.437  0.755  1.0
  O  O24  1  0.846  0.522  0.500  1.0
  O  O25  1  0.481  0.157  0.000  1.0
  O  O26  1  0.157  0.481  0.000  1.0
  O  O27  1  0.522  0.846  0.500  1.0
[/CIF]
.
The compound described by BaNb4PbBi4O18 crystallizes in the orthorhombic Amm2 space group. Ba(1) is bonded to two equivalent O(1), two equivalent O(2), four equivalent O(3), and four equivalent O(5) atoms to form BaO12 cuboctahedra that share corners with four equivalent Ba(1)O12 cuboctahedra, faces with four equivalent Nb(1)O6 octahedra, and faces with four equivalent Nb(2)O6 octahedra. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(1), one O(6), two equivalent O(3), and two equivalent O(5) atoms to form NbO6 octahedra that share  a cornercorner with one Nb(1)O6 octahedra, corners with four equivalent Nb(2)O6 octahedra, and faces with two equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 6-19°. In the second Nb site, Nb(2) is bonded to one O(2), one O(7), two equivalent O(3), and two equivalent O(5) atoms to form NbO6 octahedra that share  a cornercorner with one Nb(2)O6 octahedra, corners with four equivalent Nb(1)O6 octahedra, and faces with two equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 3-19°. Pb(1) is bonded in a 5-coordinate geometry to one O(2) and four equivalent O(5) atoms. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a distorted pentagonal planar geometry to one O(6) and four equivalent O(4) atoms. In the second Bi site, Bi(2) is bonded in a distorted pentagonal planar geometry to one O(7) and four equivalent O(4) atoms. There are seven inequivalent O sites. In the first O site, O(6) is bonded in a distorted bent 120 degrees geometry to one Nb(1) and one Bi(1) atom. In the second O site, O(7) is bonded in a distorted bent 120 degrees geometry to one Nb(2) and one Bi(2) atom. In the third O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Ba(1) and two equivalent Nb(1) atoms. In the fourth O site, O(2) is bonded to two equivalent Ba(1), two equivalent Nb(2), and one Pb(1) atom to form distorted corner-sharing OBa2Nb2Pb square pyramids. In the fifth O site, O(3) is bonded in a distorted linear geometry to one Ba(1), one Nb(1), and one Nb(2) atom. In the sixth O site, O(4) is bonded to two equivalent Bi(1) and two equivalent Bi(2) atoms to form a mixture of corner and edge-sharing OBi4 tetrahedra. In the seventh O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to one Ba(1), one Nb(1), one Nb(2), and one Pb(1) atom. is represented by the CIF file [CIF]
data_BaNb4Bi4PbO18
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.823
_cell_length_b   12.823
_cell_length_c   5.668
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   154.402
_symmetry_Int_Tables_number   1
_cell_volume   402.661
_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  0.242  0.242  0.500  1.0
  Nb  Nb1  1  0.824  0.650  0.500  1.0
  Nb  Nb2  1  0.326  0.150  0.000  1.0
  Nb  Nb3  1  0.150  0.326  0.000  1.0
  Nb  Nb4  1  0.650  0.824  0.500  1.0
  Bi  Bi5  1  0.491  0.086  0.500  1.0
  Bi  Bi6  1  0.903  0.501  0.000  1.0
  Bi  Bi7  1  0.501  0.903  0.000  1.0
  Bi  Bi8  1  0.086  0.491  0.500  1.0
  Pb  Pb9  1  0.711  0.711  0.000  1.0
  O  O10  1  0.773  0.773  0.500  1.0
  O  O11  1  0.248  0.248  0.000  1.0
  O  O12  1  0.098  0.924  0.255  1.0
  O  O13  1  0.098  0.924  0.745  1.0
  O  O14  1  0.924  0.098  0.255  1.0
  O  O15  1  0.924  0.098  0.745  1.0
  O  O16  1  0.247  0.753  0.250  1.0
  O  O17  1  0.247  0.753  0.750  1.0
  O  O18  1  0.753  0.247  0.250  1.0
  O  O19  1  0.753  0.247  0.750  1.0
  O  O20  1  0.437  0.586  0.245  1.0
  O  O21  1  0.437  0.586  0.755  1.0
  O  O22  1  0.586  0.437  0.245  1.0
  O  O23  1  0.586  0.437  0.755  1.0
  O  O24  1  0.846  0.522  0.500  1.0
  O  O25  1  0.481  0.157  0.000  1.0
  O  O26  1  0.157  0.481  0.000  1.0
  O  O27  1  0.522  0.846  0.500  1.0
[/CIF]
.