The compound described by Ba3W2O9 crystallizes in the trigonal R-3c space group. Ba(1) is bonded to four equivalent O(2) and eight equivalent O(1) atoms to form BaO12 cuboctahedra that share corners with six equivalent Ba(1)O12 cuboctahedra, corners with four equivalent W(1)O6 octahedra, faces with eight equivalent Ba(1)O12 cuboctahedra, and faces with four equivalent W(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-28°. W(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form distorted WO6 octahedra that share corners with six equivalent Ba(1)O12 cuboctahedra, faces with six equivalent Ba(1)O12 cuboctahedra, and  a faceface with one W(1)O6 octahedra. There are two inequivalent O sites. In the first O site, O(2) is bonded to four equivalent Ba(1) and two equivalent W(1) atoms to form a mixture of distorted corner, edge, and face-sharing OBa4W2 octahedra. The corner-sharing octahedral tilt angles range from 38-58°. In the second O site, O(1) is bonded in a distorted single-bond geometry to four equivalent Ba(1) and one W(1) atom. is represented by the CIF file [CIF]
data_Ba3W2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.520
_cell_length_b   7.520
_cell_length_c   7.520
_cell_angle_alpha   85.476
_cell_angle_beta   85.476
_cell_angle_gamma   85.476
_symmetry_Int_Tables_number   1
_cell_volume   421.436
_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  0.580  0.920  0.250  1.0
  Ba  Ba1  1  0.920  0.250  0.580  1.0
  Ba  Ba2  1  0.250  0.580  0.920  1.0
  Ba  Ba3  1  0.420  0.080  0.750  1.0
  Ba  Ba4  1  0.750  0.420  0.080  1.0
  Ba  Ba5  1  0.080  0.750  0.420  1.0
  W  W6  1  0.145  0.145  0.145  1.0
  W  W7  1  0.355  0.355  0.355  1.0
  W  W8  1  0.855  0.855  0.855  1.0
  W  W9  1  0.645  0.645  0.645  1.0
  O  O10  1  0.251  0.929  0.087  1.0
  O  O11  1  0.087  0.251  0.929  1.0
  O  O12  1  0.929  0.087  0.251  1.0
  O  O13  1  0.249  0.413  0.571  1.0
  O  O14  1  0.571  0.249  0.413  1.0
  O  O15  1  0.413  0.571  0.249  1.0
  O  O16  1  0.749  0.071  0.913  1.0
  O  O17  1  0.913  0.749  0.071  1.0
  O  O18  1  0.071  0.913  0.749  1.0
  O  O19  1  0.751  0.587  0.429  1.0
  O  O20  1  0.105  0.395  0.250  1.0
  O  O21  1  0.395  0.250  0.105  1.0
  O  O22  1  0.250  0.105  0.395  1.0
  O  O23  1  0.895  0.605  0.750  1.0
  O  O24  1  0.605  0.750  0.895  1.0
  O  O25  1  0.750  0.895  0.605  1.0
  O  O26  1  0.587  0.429  0.751  1.0
  O  O27  1  0.429  0.751  0.587  1.0
[/CIF]
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The compound described by Ba3W2O9 crystallizes in the trigonal R-3c space group. Ba(1) is bonded to four equivalent O(2) and eight equivalent O(1) atoms to form BaO12 cuboctahedra that share corners with six equivalent Ba(1)O12 cuboctahedra, corners with four equivalent W(1)O6 octahedra, faces with eight equivalent Ba(1)O12 cuboctahedra, and faces with four equivalent W(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-28°. W(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form distorted WO6 octahedra that share corners with six equivalent Ba(1)O12 cuboctahedra, faces with six equivalent Ba(1)O12 cuboctahedra, and  a faceface with one W(1)O6 octahedra. There are two inequivalent O sites. In the first O site, O(2) is bonded to four equivalent Ba(1) and two equivalent W(1) atoms to form a mixture of distorted corner, edge, and face-sharing OBa4W2 octahedra. The corner-sharing octahedral tilt angles range from 38-58°. In the second O site, O(1) is bonded in a distorted single-bond geometry to four equivalent Ba(1) and one W(1) atom. is represented by the CIF file [CIF]
data_Ba3W2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.520
_cell_length_b   7.520
_cell_length_c   7.520
_cell_angle_alpha   85.476
_cell_angle_beta   85.476
_cell_angle_gamma   85.476
_symmetry_Int_Tables_number   1
_cell_volume   421.436
_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  0.580  0.920  0.250  1.0
  Ba  Ba1  1  0.920  0.250  0.580  1.0
  Ba  Ba2  1  0.250  0.580  0.920  1.0
  Ba  Ba3  1  0.420  0.080  0.750  1.0
  Ba  Ba4  1  0.750  0.420  0.080  1.0
  Ba  Ba5  1  0.080  0.750  0.420  1.0
  W  W6  1  0.145  0.145  0.145  1.0
  W  W7  1  0.355  0.355  0.355  1.0
  W  W8  1  0.855  0.855  0.855  1.0
  W  W9  1  0.645  0.645  0.645  1.0
  O  O10  1  0.251  0.929  0.087  1.0
  O  O11  1  0.087  0.251  0.929  1.0
  O  O12  1  0.929  0.087  0.251  1.0
  O  O13  1  0.249  0.413  0.571  1.0
  O  O14  1  0.571  0.249  0.413  1.0
  O  O15  1  0.413  0.571  0.249  1.0
  O  O16  1  0.749  0.071  0.913  1.0
  O  O17  1  0.913  0.749  0.071  1.0
  O  O18  1  0.071  0.913  0.749  1.0
  O  O19  1  0.751  0.587  0.429  1.0
  O  O20  1  0.105  0.395  0.250  1.0
  O  O21  1  0.395  0.250  0.105  1.0
  O  O22  1  0.250  0.105  0.395  1.0
  O  O23  1  0.895  0.605  0.750  1.0
  O  O24  1  0.605  0.750  0.895  1.0
  O  O25  1  0.750  0.895  0.605  1.0
  O  O26  1  0.587  0.429  0.751  1.0
  O  O27  1  0.429  0.751  0.587  1.0
[/CIF]
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