The material structure described by Ba3SrNb2O9 crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to six equivalent O(1) and six equivalent O(2) atoms to form BaO12 cuboctahedra that share corners with six equivalent Ba(1)O12 cuboctahedra, faces with two equivalent Sr(1)O6 octahedra, and faces with six equivalent Nb(1)O6 octahedra. In the second Ba site, Ba(2) is bonded in a 9-coordinate geometry to three equivalent O(1) and six equivalent O(2) atoms. Sr(1) is bonded to six equivalent O(2) atoms to form SrO6 octahedra that share corners with six equivalent Nb(1)O6 octahedra and faces with two equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 15°. Nb(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form distorted NbO6 octahedra that share corners with three equivalent Sr(1)O6 octahedra, faces with three equivalent Ba(1)O12 cuboctahedra, and  a faceface with one Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles are 15°. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ba(1), two equivalent Ba(2), and two equivalent Nb(1) atoms to form a mixture of distorted corner and face-sharing OBa4Nb2 octahedra. The corner-sharing octahedral tilt angles range from 6-60°. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Ba(1), two equivalent Ba(2), one Sr(1), and one Nb(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ba3SrNb2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.100
_cell_length_b   6.100
_cell_length_c   16.111
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   519.236
_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
  Ba  Ba0  1  0.000  0.000  0.250  1.0
  Ba  Ba1  1  0.000  0.000  0.750  1.0
  Ba  Ba2  1  0.333  0.667  0.873  1.0
  Ba  Ba3  1  0.667  0.333  0.373  1.0
  Ba  Ba4  1  0.667  0.333  0.127  1.0
  Ba  Ba5  1  0.333  0.667  0.627  1.0
  Sr  Sr6  1  0.000  0.000  0.000  1.0
  Sr  Sr7  1  0.000  0.000  0.500  1.0
  Nb  Nb8  1  0.333  0.667  0.156  1.0
  Nb  Nb9  1  0.667  0.333  0.656  1.0
  Nb  Nb10  1  0.667  0.333  0.844  1.0
  Nb  Nb11  1  0.333  0.667  0.344  1.0
  O  O12  1  0.484  0.968  0.250  1.0
  O  O13  1  0.516  0.484  0.750  1.0
  O  O14  1  0.968  0.484  0.750  1.0
  O  O15  1  0.032  0.516  0.250  1.0
  O  O16  1  0.484  0.516  0.250  1.0
  O  O17  1  0.516  0.032  0.750  1.0
  O  O18  1  0.172  0.345  0.398  1.0
  O  O19  1  0.828  0.172  0.898  1.0
  O  O20  1  0.345  0.172  0.898  1.0
  O  O21  1  0.655  0.828  0.398  1.0
  O  O22  1  0.172  0.828  0.398  1.0
  O  O23  1  0.828  0.655  0.602  1.0
  O  O24  1  0.828  0.172  0.602  1.0
  O  O25  1  0.828  0.655  0.898  1.0
  O  O26  1  0.345  0.172  0.602  1.0
  O  O27  1  0.655  0.828  0.102  1.0
  O  O28  1  0.172  0.345  0.102  1.0
  O  O29  1  0.172  0.828  0.102  1.0
[/CIF]
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The material structure described by Ba3SrNb2O9 crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to six equivalent O(1) and six equivalent O(2) atoms to form BaO12 cuboctahedra that share corners with six equivalent Ba(1)O12 cuboctahedra, faces with two equivalent Sr(1)O6 octahedra, and faces with six equivalent Nb(1)O6 octahedra. In the second Ba site, Ba(2) is bonded in a 9-coordinate geometry to three equivalent O(1) and six equivalent O(2) atoms. Sr(1) is bonded to six equivalent O(2) atoms to form SrO6 octahedra that share corners with six equivalent Nb(1)O6 octahedra and faces with two equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 15°. Nb(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form distorted NbO6 octahedra that share corners with three equivalent Sr(1)O6 octahedra, faces with three equivalent Ba(1)O12 cuboctahedra, and  a faceface with one Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles are 15°. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ba(1), two equivalent Ba(2), and two equivalent Nb(1) atoms to form a mixture of distorted corner and face-sharing OBa4Nb2 octahedra. The corner-sharing octahedral tilt angles range from 6-60°. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Ba(1), two equivalent Ba(2), one Sr(1), and one Nb(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ba3SrNb2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.100
_cell_length_b   6.100
_cell_length_c   16.111
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   519.236
_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
  Ba  Ba0  1  0.000  0.000  0.250  1.0
  Ba  Ba1  1  0.000  0.000  0.750  1.0
  Ba  Ba2  1  0.333  0.667  0.873  1.0
  Ba  Ba3  1  0.667  0.333  0.373  1.0
  Ba  Ba4  1  0.667  0.333  0.127  1.0
  Ba  Ba5  1  0.333  0.667  0.627  1.0
  Sr  Sr6  1  0.000  0.000  0.000  1.0
  Sr  Sr7  1  0.000  0.000  0.500  1.0
  Nb  Nb8  1  0.333  0.667  0.156  1.0
  Nb  Nb9  1  0.667  0.333  0.656  1.0
  Nb  Nb10  1  0.667  0.333  0.844  1.0
  Nb  Nb11  1  0.333  0.667  0.344  1.0
  O  O12  1  0.484  0.968  0.250  1.0
  O  O13  1  0.516  0.484  0.750  1.0
  O  O14  1  0.968  0.484  0.750  1.0
  O  O15  1  0.032  0.516  0.250  1.0
  O  O16  1  0.484  0.516  0.250  1.0
  O  O17  1  0.516  0.032  0.750  1.0
  O  O18  1  0.172  0.345  0.398  1.0
  O  O19  1  0.828  0.172  0.898  1.0
  O  O20  1  0.345  0.172  0.898  1.0
  O  O21  1  0.655  0.828  0.398  1.0
  O  O22  1  0.172  0.828  0.398  1.0
  O  O23  1  0.828  0.655  0.602  1.0
  O  O24  1  0.828  0.172  0.602  1.0
  O  O25  1  0.828  0.655  0.898  1.0
  O  O26  1  0.345  0.172  0.602  1.0
  O  O27  1  0.655  0.828  0.102  1.0
  O  O28  1  0.172  0.345  0.102  1.0
  O  O29  1  0.172  0.828  0.102  1.0
[/CIF]
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