The compound described by Na2CaNb4Bi2O15 crystallizes in the orthorhombic Cmc2_1 space group. Na(1) is bonded in a 9-coordinate geometry to one O(8), two equivalent O(5), two equivalent O(7), and four equivalent O(2) atoms. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(4), two equivalent O(8), and four equivalent O(1) atoms. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(8) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 5-34°. In the second Nb site, Nb(2) is bonded to one O(2), one O(6), two equivalent O(5), and two equivalent O(7) atoms to form distorted corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 5-27°. Bi(1) is bonded in a 6-coordinate geometry to two equivalent O(6) and four equivalent O(3) atoms. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Ca(1) and two equivalent Nb(1) atoms. In the second O site, O(2) is bonded in a 6-coordinate geometry to four equivalent Na(1), one Nb(1), and one Nb(2) atom. In the third O site, O(3) is bonded to four equivalent Bi(1) atoms to form a mixture of corner and edge-sharing OBi4 tetrahedra. In the fourth O site, O(4) is bonded in a distorted see-saw-like geometry to two equivalent Ca(1) and two equivalent Nb(1) atoms. In the fifth O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na(1) and two equivalent Nb(2) atoms. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Nb(2) and two equivalent Bi(1) atoms. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to two equivalent Na(1) and two equivalent Nb(2) atoms. In the eighth O site, O(8) is bonded in a distorted see-saw-like geometry to one Na(1), one Ca(1), and two equivalent Nb(1) atoms. is represented by the CIF file [CIF]
data_Na2CaNb4Bi2O15
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   20.978
_cell_length_b   20.978
_cell_length_c   5.572
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   164.812
_symmetry_Int_Tables_number   1
_cell_volume   642.457
_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
  Na  Na0  1  0.132  0.339  0.534  1.0
  Na  Na1  1  0.339  0.132  0.534  1.0
  Na  Na2  1  0.868  0.661  0.034  1.0
  Na  Na3  1  0.661  0.868  0.034  1.0
  Ca  Ca4  1  0.754  0.754  0.018  1.0
  Ca  Ca5  1  0.246  0.246  0.518  1.0
  Nb  Nb6  1  0.706  0.807  0.547  1.0
  Nb  Nb7  1  0.807  0.706  0.547  1.0
  Nb  Nb8  1  0.294  0.193  0.047  1.0
  Nb  Nb9  1  0.193  0.294  0.047  1.0
  Nb  Nb10  1  0.591  0.892  0.538  1.0
  Nb  Nb11  1  0.892  0.591  0.538  1.0
  Nb  Nb12  1  0.409  0.108  0.038  1.0
  Nb  Nb13  1  0.108  0.409  0.038  1.0
  Bi  Bi14  1  0.056  0.495  0.486  1.0
  Bi  Bi15  1  0.495  0.056  0.486  1.0
  Bi  Bi16  1  0.944  0.505  0.986  1.0
  Bi  Bi17  1  0.505  0.944  0.986  1.0
  O  O18  1  0.407  0.491  0.769  1.0
  O  O19  1  0.491  0.407  0.769  1.0
  O  O20  1  0.593  0.509  0.269  1.0
  O  O21  1  0.509  0.593  0.269  1.0
  O  O22  1  0.642  0.834  0.556  1.0
  O  O23  1  0.834  0.642  0.556  1.0
  O  O24  1  0.358  0.166  0.056  1.0
  O  O25  1  0.166  0.358  0.056  1.0
  O  O26  1  0.743  0.241  0.765  1.0
  O  O27  1  0.241  0.743  0.765  1.0
  O  O28  1  0.257  0.759  0.265  1.0
  O  O29  1  0.759  0.257  0.265  1.0
  O  O30  1  0.192  0.192  0.086  1.0
  O  O31  1  0.808  0.808  0.586  1.0
  O  O32  1  0.882  0.174  0.778  1.0
  O  O33  1  0.174  0.882  0.778  1.0
  O  O34  1  0.118  0.826  0.278  1.0
  O  O35  1  0.826  0.118  0.278  1.0
  O  O36  1  0.510  0.901  0.567  1.0
  O  O37  1  0.901  0.510  0.567  1.0
  O  O38  1  0.490  0.099  0.067  1.0
  O  O39  1  0.099  0.490  0.067  1.0
  O  O40  1  0.393  0.679  0.840  1.0
  O  O41  1  0.679  0.393  0.840  1.0
  O  O42  1  0.607  0.321  0.340  1.0
  O  O43  1  0.321  0.607  0.340  1.0
  O  O44  1  0.883  0.984  0.882  1.0
  O  O45  1  0.984  0.883  0.882  1.0
  O  O46  1  0.117  0.016  0.382  1.0
  O  O47  1  0.016  0.117  0.382  1.0
[/CIF]
.
The compound described by Na2CaNb4Bi2O15 crystallizes in the orthorhombic Cmc2_1 space group. Na(1) is bonded in a 9-coordinate geometry to one O(8), two equivalent O(5), two equivalent O(7), and four equivalent O(2) atoms. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(4), two equivalent O(8), and four equivalent O(1) atoms. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(8) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 5-34°. In the second Nb site, Nb(2) is bonded to one O(2), one O(6), two equivalent O(5), and two equivalent O(7) atoms to form distorted corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 5-27°. Bi(1) is bonded in a 6-coordinate geometry to two equivalent O(6) and four equivalent O(3) atoms. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Ca(1) and two equivalent Nb(1) atoms. In the second O site, O(2) is bonded in a 6-coordinate geometry to four equivalent Na(1), one Nb(1), and one Nb(2) atom. In the third O site, O(3) is bonded to four equivalent Bi(1) atoms to form a mixture of corner and edge-sharing OBi4 tetrahedra. In the fourth O site, O(4) is bonded in a distorted see-saw-like geometry to two equivalent Ca(1) and two equivalent Nb(1) atoms. In the fifth O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na(1) and two equivalent Nb(2) atoms. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Nb(2) and two equivalent Bi(1) atoms. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to two equivalent Na(1) and two equivalent Nb(2) atoms. In the eighth O site, O(8) is bonded in a distorted see-saw-like geometry to one Na(1), one Ca(1), and two equivalent Nb(1) atoms. is represented by the CIF file [CIF]
data_Na2CaNb4Bi2O15
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   20.978
_cell_length_b   20.978
_cell_length_c   5.572
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   164.812
_symmetry_Int_Tables_number   1
_cell_volume   642.457
_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
  Na  Na0  1  0.132  0.339  0.534  1.0
  Na  Na1  1  0.339  0.132  0.534  1.0
  Na  Na2  1  0.868  0.661  0.034  1.0
  Na  Na3  1  0.661  0.868  0.034  1.0
  Ca  Ca4  1  0.754  0.754  0.018  1.0
  Ca  Ca5  1  0.246  0.246  0.518  1.0
  Nb  Nb6  1  0.706  0.807  0.547  1.0
  Nb  Nb7  1  0.807  0.706  0.547  1.0
  Nb  Nb8  1  0.294  0.193  0.047  1.0
  Nb  Nb9  1  0.193  0.294  0.047  1.0
  Nb  Nb10  1  0.591  0.892  0.538  1.0
  Nb  Nb11  1  0.892  0.591  0.538  1.0
  Nb  Nb12  1  0.409  0.108  0.038  1.0
  Nb  Nb13  1  0.108  0.409  0.038  1.0
  Bi  Bi14  1  0.056  0.495  0.486  1.0
  Bi  Bi15  1  0.495  0.056  0.486  1.0
  Bi  Bi16  1  0.944  0.505  0.986  1.0
  Bi  Bi17  1  0.505  0.944  0.986  1.0
  O  O18  1  0.407  0.491  0.769  1.0
  O  O19  1  0.491  0.407  0.769  1.0
  O  O20  1  0.593  0.509  0.269  1.0
  O  O21  1  0.509  0.593  0.269  1.0
  O  O22  1  0.642  0.834  0.556  1.0
  O  O23  1  0.834  0.642  0.556  1.0
  O  O24  1  0.358  0.166  0.056  1.0
  O  O25  1  0.166  0.358  0.056  1.0
  O  O26  1  0.743  0.241  0.765  1.0
  O  O27  1  0.241  0.743  0.765  1.0
  O  O28  1  0.257  0.759  0.265  1.0
  O  O29  1  0.759  0.257  0.265  1.0
  O  O30  1  0.192  0.192  0.086  1.0
  O  O31  1  0.808  0.808  0.586  1.0
  O  O32  1  0.882  0.174  0.778  1.0
  O  O33  1  0.174  0.882  0.778  1.0
  O  O34  1  0.118  0.826  0.278  1.0
  O  O35  1  0.826  0.118  0.278  1.0
  O  O36  1  0.510  0.901  0.567  1.0
  O  O37  1  0.901  0.510  0.567  1.0
  O  O38  1  0.490  0.099  0.067  1.0
  O  O39  1  0.099  0.490  0.067  1.0
  O  O40  1  0.393  0.679  0.840  1.0
  O  O41  1  0.679  0.393  0.840  1.0
  O  O42  1  0.607  0.321  0.340  1.0
  O  O43  1  0.321  0.607  0.340  1.0
  O  O44  1  0.883  0.984  0.882  1.0
  O  O45  1  0.984  0.883  0.882  1.0
  O  O46  1  0.117  0.016  0.382  1.0
  O  O47  1  0.016  0.117  0.382  1.0
[/CIF]
.