The material described by Sr5Nb4O15 crystallizes in the trigonal P-3c1 space group. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 6-coordinate geometry to three equivalent O(1) and three equivalent O(2) atoms. In the second Sr site, Sr(2) is bonded in a 6-coordinate geometry to six equivalent O(1) atoms. In the third Sr site, Sr(3) is bonded to three equivalent O(3) and six equivalent O(2) atoms to form distorted SrO9 cuboctahedra that share edges with six equivalent Nb(1)O6 octahedra and faces with two equivalent Nb(2)O6 octahedra. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to three equivalent O(2) and three equivalent O(3) atoms to form NbO6 octahedra that share corners with three equivalent Nb(1)O6 octahedra, corners with three equivalent Nb(2)O6 octahedra, and edges with three equivalent Sr(3)O9 cuboctahedra. The corner-sharing octahedral tilt angles range from 15-19°. In the second Nb site, Nb(2) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form distorted NbO6 octahedra that share corners with three equivalent Nb(1)O6 octahedra and  a faceface with one Sr(3)O9 cuboctahedra. The corner-sharing octahedral tilt angles are 19°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Sr(1), two equivalent Sr(2), and one Nb(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(3), one Nb(1), and one Nb(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Sr(3) and two equivalent Nb(1) atoms. is represented by the CIF card [CIF]
data_Sr5Nb4O15
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.708
_cell_length_b   5.708
_cell_length_c   23.054
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   650.504
_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
  Sr  Sr0  1  0.333  0.667  0.141  1.0
  Sr  Sr1  1  0.333  0.667  0.471  1.0
  Sr  Sr2  1  0.000  0.000  0.250  1.0
  Sr  Sr3  1  1.000  1.000  0.750  1.0
  Sr  Sr4  1  0.333  0.667  0.641  1.0
  Sr  Sr5  1  0.333  0.667  0.971  1.0
  Sr  Sr6  1  0.667  0.333  0.029  1.0
  Sr  Sr7  1  0.667  0.333  0.359  1.0
  Sr  Sr8  1  0.667  0.333  0.529  1.0
  Sr  Sr9  1  0.667  0.333  0.859  1.0
  Nb  Nb10  1  0.333  0.667  0.303  1.0
  Nb  Nb11  1  1.000  1.000  0.090  1.0
  Nb  Nb12  1  0.000  0.000  0.410  1.0
  Nb  Nb13  1  1.000  0.000  0.590  1.0
  Nb  Nb14  1  0.000  0.000  0.910  1.0
  Nb  Nb15  1  0.333  0.667  0.803  1.0
  Nb  Nb16  1  0.667  0.333  0.197  1.0
  Nb  Nb17  1  0.667  0.333  0.697  1.0
  O  O18  1  0.100  0.766  0.555  1.0
  O  O19  1  0.115  0.784  0.346  1.0
  O  O20  1  0.000  0.547  0.750  1.0
  O  O21  1  1.000  0.453  0.250  1.0
  O  O22  1  0.216  0.885  0.846  1.0
  O  O23  1  0.234  0.900  0.055  1.0
  O  O24  1  0.100  0.334  0.055  1.0
  O  O25  1  0.115  0.331  0.846  1.0
  O  O26  1  0.216  0.331  0.346  1.0
  O  O27  1  0.234  0.334  0.555  1.0
  O  O28  1  0.334  0.234  0.945  1.0
  O  O29  1  0.666  0.900  0.555  1.0
  O  O30  1  0.669  0.885  0.346  1.0
  O  O31  1  0.331  0.216  0.154  1.0
  O  O32  1  0.453  0.453  0.750  1.0
  O  O33  1  0.547  0.547  0.250  1.0
  O  O34  1  0.669  0.784  0.846  1.0
  O  O35  1  0.331  0.115  0.654  1.0
  O  O36  1  0.334  0.100  0.445  1.0
  O  O37  1  0.666  0.766  0.055  1.0
  O  O38  1  0.766  0.666  0.445  1.0
  O  O39  1  0.784  0.669  0.654  1.0
  O  O40  1  0.453  0.000  0.250  1.0
  O  O41  1  0.547  1.000  0.750  1.0
  O  O42  1  0.885  0.669  0.154  1.0
  O  O43  1  0.900  0.666  0.945  1.0
  O  O44  1  0.766  0.100  0.945  1.0
  O  O45  1  0.784  0.115  0.154  1.0
  O  O46  1  0.885  0.216  0.654  1.0
  O  O47  1  0.900  0.234  0.445  1.0
[/CIF]
.
The material described by Sr5Nb4O15 crystallizes in the trigonal P-3c1 space group. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 6-coordinate geometry to three equivalent O(1) and three equivalent O(2) atoms. In the second Sr site, Sr(2) is bonded in a 6-coordinate geometry to six equivalent O(1) atoms. In the third Sr site, Sr(3) is bonded to three equivalent O(3) and six equivalent O(2) atoms to form distorted SrO9 cuboctahedra that share edges with six equivalent Nb(1)O6 octahedra and faces with two equivalent Nb(2)O6 octahedra. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to three equivalent O(2) and three equivalent O(3) atoms to form NbO6 octahedra that share corners with three equivalent Nb(1)O6 octahedra, corners with three equivalent Nb(2)O6 octahedra, and edges with three equivalent Sr(3)O9 cuboctahedra. The corner-sharing octahedral tilt angles range from 15-19°. In the second Nb site, Nb(2) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form distorted NbO6 octahedra that share corners with three equivalent Nb(1)O6 octahedra and  a faceface with one Sr(3)O9 cuboctahedra. The corner-sharing octahedral tilt angles are 19°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Sr(1), two equivalent Sr(2), and one Nb(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(3), one Nb(1), and one Nb(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Sr(3) and two equivalent Nb(1) atoms. is represented by the CIF card [CIF]
data_Sr5Nb4O15
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.708
_cell_length_b   5.708
_cell_length_c   23.054
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   650.504
_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
  Sr  Sr0  1  0.333  0.667  0.141  1.0
  Sr  Sr1  1  0.333  0.667  0.471  1.0
  Sr  Sr2  1  0.000  0.000  0.250  1.0
  Sr  Sr3  1  1.000  1.000  0.750  1.0
  Sr  Sr4  1  0.333  0.667  0.641  1.0
  Sr  Sr5  1  0.333  0.667  0.971  1.0
  Sr  Sr6  1  0.667  0.333  0.029  1.0
  Sr  Sr7  1  0.667  0.333  0.359  1.0
  Sr  Sr8  1  0.667  0.333  0.529  1.0
  Sr  Sr9  1  0.667  0.333  0.859  1.0
  Nb  Nb10  1  0.333  0.667  0.303  1.0
  Nb  Nb11  1  1.000  1.000  0.090  1.0
  Nb  Nb12  1  0.000  0.000  0.410  1.0
  Nb  Nb13  1  1.000  0.000  0.590  1.0
  Nb  Nb14  1  0.000  0.000  0.910  1.0
  Nb  Nb15  1  0.333  0.667  0.803  1.0
  Nb  Nb16  1  0.667  0.333  0.197  1.0
  Nb  Nb17  1  0.667  0.333  0.697  1.0
  O  O18  1  0.100  0.766  0.555  1.0
  O  O19  1  0.115  0.784  0.346  1.0
  O  O20  1  0.000  0.547  0.750  1.0
  O  O21  1  1.000  0.453  0.250  1.0
  O  O22  1  0.216  0.885  0.846  1.0
  O  O23  1  0.234  0.900  0.055  1.0
  O  O24  1  0.100  0.334  0.055  1.0
  O  O25  1  0.115  0.331  0.846  1.0
  O  O26  1  0.216  0.331  0.346  1.0
  O  O27  1  0.234  0.334  0.555  1.0
  O  O28  1  0.334  0.234  0.945  1.0
  O  O29  1  0.666  0.900  0.555  1.0
  O  O30  1  0.669  0.885  0.346  1.0
  O  O31  1  0.331  0.216  0.154  1.0
  O  O32  1  0.453  0.453  0.750  1.0
  O  O33  1  0.547  0.547  0.250  1.0
  O  O34  1  0.669  0.784  0.846  1.0
  O  O35  1  0.331  0.115  0.654  1.0
  O  O36  1  0.334  0.100  0.445  1.0
  O  O37  1  0.666  0.766  0.055  1.0
  O  O38  1  0.766  0.666  0.445  1.0
  O  O39  1  0.784  0.669  0.654  1.0
  O  O40  1  0.453  0.000  0.250  1.0
  O  O41  1  0.547  1.000  0.750  1.0
  O  O42  1  0.885  0.669  0.154  1.0
  O  O43  1  0.900  0.666  0.945  1.0
  O  O44  1  0.766  0.100  0.945  1.0
  O  O45  1  0.784  0.115  0.154  1.0
  O  O46  1  0.885  0.216  0.654  1.0
  O  O47  1  0.900  0.234  0.445  1.0
[/CIF]
.