The crystal structure described by Pr2W2O9 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Pr sites. In the first Pr site, Pr(1) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(4), one O(6), one O(7), one O(8), one O(9), and two equivalent O(3) atoms. In the second Pr site, Pr(2) is bonded in a 9-coordinate geometry to one O(1), one O(5), one O(6), one O(7), one O(9), two equivalent O(2), and two equivalent O(8) atoms. There are two inequivalent W sites. In the first W site, W(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(9) atom to form a mixture of distorted edge and corner-sharing WO6 octahedra. The corner-sharing octahedral tilt angles are 42°. In the second W site, W(2) is bonded to one O(4), one O(5), one O(6), one O(7), one O(8), and one O(9) atom to form a mixture of distorted edge and corner-sharing WO6 octahedra. The corner-sharing octahedral tilt angles are 42°. There are nine inequivalent O sites. In the first O site, O(5) is bonded in a distorted trigonal planar geometry to one Pr(2), one W(1), and one W(2) atom. In the second O site, O(6) is bonded in a 3-coordinate geometry to one Pr(1), one Pr(2), and one W(2) atom. In the third O site, O(7) is bonded in a 3-coordinate geometry to one Pr(1), one Pr(2), and one W(2) atom. In the fourth O site, O(8) is bonded to one Pr(1), two equivalent Pr(2), and one W(2) atom to form edge-sharing OPr3W tetrahedra. In the fifth O site, O(1) is bonded in a 3-coordinate geometry to one Pr(1), one Pr(2), and one W(1) atom. In the sixth O site, O(9) is bonded in a 4-coordinate geometry to one Pr(1), one Pr(2), one W(1), and one W(2) atom. In the seventh O site, O(2) is bonded in a 3-coordinate geometry to one Pr(1), two equivalent Pr(2), and one W(1) atom. In the eighth O site, O(3) is bonded in a 3-coordinate geometry to two equivalent Pr(1) and one W(1) atom. In the ninth O site, O(4) is bonded in a 3-coordinate geometry to one Pr(1), one W(1), and one W(2) atom. is represented by the CIF file [CIF]
data_Pr2W2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.946
_cell_length_b   7.698
_cell_length_c   9.299
_cell_angle_alpha   72.651
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   679.543
_cell_formula_units_Z   4
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
  Pr  Pr0  1  0.052  0.228  0.347  1.0
  Pr  Pr1  1  0.552  0.772  0.153  1.0
  Pr  Pr2  1  0.948  0.772  0.653  1.0
  Pr  Pr3  1  0.448  0.228  0.847  1.0
  Pr  Pr4  1  0.454  0.281  0.426  1.0
  Pr  Pr5  1  0.954  0.719  0.074  1.0
  Pr  Pr6  1  0.546  0.719  0.574  1.0
  Pr  Pr7  1  0.046  0.281  0.926  1.0
  W  W8  1  0.751  0.072  0.262  1.0
  W  W9  1  0.251  0.928  0.238  1.0
  W  W10  1  0.249  0.928  0.738  1.0
  W  W11  1  0.749  0.072  0.762  1.0
  W  W12  1  0.773  0.425  0.465  1.0
  W  W13  1  0.273  0.575  0.035  1.0
  W  W14  1  0.227  0.575  0.535  1.0
  W  W15  1  0.727  0.425  0.965  1.0
  O  O16  1  0.780  0.902  0.161  1.0
  O  O17  1  0.280  0.098  0.339  1.0
  O  O18  1  0.220  0.098  0.839  1.0
  O  O19  1  0.720  0.902  0.661  1.0
  O  O20  1  0.590  0.956  0.342  1.0
  O  O21  1  0.090  0.044  0.158  1.0
  O  O22  1  0.410  0.044  0.658  1.0
  O  O23  1  0.910  0.956  0.842  1.0
  O  O24  1  0.878  0.989  0.404  1.0
  O  O25  1  0.378  0.011  0.096  1.0
  O  O26  1  0.122  0.011  0.596  1.0
  O  O27  1  0.622  0.989  0.904  1.0
  O  O28  1  0.623  0.229  0.078  1.0
  O  O29  1  0.123  0.771  0.422  1.0
  O  O30  1  0.377  0.771  0.922  1.0
  O  O31  1  0.877  0.229  0.578  1.0
  O  O32  1  0.810  0.260  0.860  1.0
  O  O33  1  0.310  0.740  0.640  1.0
  O  O34  1  0.190  0.740  0.140  1.0
  O  O35  1  0.690  0.260  0.360  1.0
  O  O36  1  0.597  0.507  0.825  1.0
  O  O37  1  0.097  0.493  0.675  1.0
  O  O38  1  0.403  0.493  0.175  1.0
  O  O39  1  0.903  0.507  0.325  1.0
  O  O40  1  0.790  0.588  0.573  1.0
  O  O41  1  0.290  0.412  0.927  1.0
  O  O42  1  0.210  0.412  0.427  1.0
  O  O43  1  0.710  0.588  0.073  1.0
  O  O44  1  0.606  0.553  0.393  1.0
  O  O45  1  0.106  0.447  0.107  1.0
  O  O46  1  0.394  0.447  0.607  1.0
  O  O47  1  0.894  0.553  0.893  1.0
  O  O48  1  0.635  0.262  0.640  1.0
  O  O49  1  0.135  0.738  0.860  1.0
  O  O50  1  0.365  0.738  0.360  1.0
  O  O51  1  0.865  0.262  0.140  1.0
[/CIF]
.
The crystal structure described by Pr2W2O9 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Pr sites. In the first Pr site, Pr(1) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(4), one O(6), one O(7), one O(8), one O(9), and two equivalent O(3) atoms. In the second Pr site, Pr(2) is bonded in a 9-coordinate geometry to one O(1), one O(5), one O(6), one O(7), one O(9), two equivalent O(2), and two equivalent O(8) atoms. There are two inequivalent W sites. In the first W site, W(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(9) atom to form a mixture of distorted edge and corner-sharing WO6 octahedra. The corner-sharing octahedral tilt angles are 42°. In the second W site, W(2) is bonded to one O(4), one O(5), one O(6), one O(7), one O(8), and one O(9) atom to form a mixture of distorted edge and corner-sharing WO6 octahedra. The corner-sharing octahedral tilt angles are 42°. There are nine inequivalent O sites. In the first O site, O(5) is bonded in a distorted trigonal planar geometry to one Pr(2), one W(1), and one W(2) atom. In the second O site, O(6) is bonded in a 3-coordinate geometry to one Pr(1), one Pr(2), and one W(2) atom. In the third O site, O(7) is bonded in a 3-coordinate geometry to one Pr(1), one Pr(2), and one W(2) atom. In the fourth O site, O(8) is bonded to one Pr(1), two equivalent Pr(2), and one W(2) atom to form edge-sharing OPr3W tetrahedra. In the fifth O site, O(1) is bonded in a 3-coordinate geometry to one Pr(1), one Pr(2), and one W(1) atom. In the sixth O site, O(9) is bonded in a 4-coordinate geometry to one Pr(1), one Pr(2), one W(1), and one W(2) atom. In the seventh O site, O(2) is bonded in a 3-coordinate geometry to one Pr(1), two equivalent Pr(2), and one W(1) atom. In the eighth O site, O(3) is bonded in a 3-coordinate geometry to two equivalent Pr(1) and one W(1) atom. In the ninth O site, O(4) is bonded in a 3-coordinate geometry to one Pr(1), one W(1), and one W(2) atom. is represented by the CIF file [CIF]
data_Pr2W2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.946
_cell_length_b   7.698
_cell_length_c   9.299
_cell_angle_alpha   72.651
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   679.543
_cell_formula_units_Z   4
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
  Pr  Pr0  1  0.052  0.228  0.347  1.0
  Pr  Pr1  1  0.552  0.772  0.153  1.0
  Pr  Pr2  1  0.948  0.772  0.653  1.0
  Pr  Pr3  1  0.448  0.228  0.847  1.0
  Pr  Pr4  1  0.454  0.281  0.426  1.0
  Pr  Pr5  1  0.954  0.719  0.074  1.0
  Pr  Pr6  1  0.546  0.719  0.574  1.0
  Pr  Pr7  1  0.046  0.281  0.926  1.0
  W  W8  1  0.751  0.072  0.262  1.0
  W  W9  1  0.251  0.928  0.238  1.0
  W  W10  1  0.249  0.928  0.738  1.0
  W  W11  1  0.749  0.072  0.762  1.0
  W  W12  1  0.773  0.425  0.465  1.0
  W  W13  1  0.273  0.575  0.035  1.0
  W  W14  1  0.227  0.575  0.535  1.0
  W  W15  1  0.727  0.425  0.965  1.0
  O  O16  1  0.780  0.902  0.161  1.0
  O  O17  1  0.280  0.098  0.339  1.0
  O  O18  1  0.220  0.098  0.839  1.0
  O  O19  1  0.720  0.902  0.661  1.0
  O  O20  1  0.590  0.956  0.342  1.0
  O  O21  1  0.090  0.044  0.158  1.0
  O  O22  1  0.410  0.044  0.658  1.0
  O  O23  1  0.910  0.956  0.842  1.0
  O  O24  1  0.878  0.989  0.404  1.0
  O  O25  1  0.378  0.011  0.096  1.0
  O  O26  1  0.122  0.011  0.596  1.0
  O  O27  1  0.622  0.989  0.904  1.0
  O  O28  1  0.623  0.229  0.078  1.0
  O  O29  1  0.123  0.771  0.422  1.0
  O  O30  1  0.377  0.771  0.922  1.0
  O  O31  1  0.877  0.229  0.578  1.0
  O  O32  1  0.810  0.260  0.860  1.0
  O  O33  1  0.310  0.740  0.640  1.0
  O  O34  1  0.190  0.740  0.140  1.0
  O  O35  1  0.690  0.260  0.360  1.0
  O  O36  1  0.597  0.507  0.825  1.0
  O  O37  1  0.097  0.493  0.675  1.0
  O  O38  1  0.403  0.493  0.175  1.0
  O  O39  1  0.903  0.507  0.325  1.0
  O  O40  1  0.790  0.588  0.573  1.0
  O  O41  1  0.290  0.412  0.927  1.0
  O  O42  1  0.210  0.412  0.427  1.0
  O  O43  1  0.710  0.588  0.073  1.0
  O  O44  1  0.606  0.553  0.393  1.0
  O  O45  1  0.106  0.447  0.107  1.0
  O  O46  1  0.394  0.447  0.607  1.0
  O  O47  1  0.894  0.553  0.893  1.0
  O  O48  1  0.635  0.262  0.640  1.0
  O  O49  1  0.135  0.738  0.860  1.0
  O  O50  1  0.365  0.738  0.360  1.0
  O  O51  1  0.865  0.262  0.140  1.0
[/CIF]
.