The crystal structure described by Pr2Se3 crystallizes in the tetragonal I-42d space group. There are three inequivalent Pr sites. In the first Pr site, Pr(1) is bonded to two equivalent Se(2), two equivalent Se(3), and four equivalent Se(1) atoms to form a mixture of distorted edge, face, and corner-sharing PrSe8 hexagonal bipyramids. In the second Pr site, Pr(2) is bonded to two equivalent Se(1), two equivalent Se(3), and four equivalent Se(2) atoms to form a mixture of distorted edge, face, and corner-sharing PrSe8 hexagonal bipyramids. In the third Pr site, Pr(3) is bonded in a 8-coordinate geometry to two equivalent Se(2), three equivalent Se(1), and three equivalent Se(3) atoms. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to one Pr(2), two equivalent Pr(1), and three equivalent Pr(3) atoms to form distorted SePr6 octahedra that share corners with three equivalent Se(1)Pr6 octahedra, corners with five equivalent Se(2)Pr5 square pyramids, corners with seven equivalent Se(3)Pr5 square pyramids, edges with two equivalent Se(1)Pr6 octahedra,  an edgeedge with one Se(3)Pr5 square pyramid, edges with three equivalent Se(2)Pr5 square pyramids, faces with two equivalent Se(1)Pr6 octahedra,  a faceface with one Se(2)Pr5 square pyramid, and faces with two equivalent Se(3)Pr5 square pyramids. The corner-sharing octahedral tilt angles range from 18-49°. In the second Se site, Se(2) is bonded to one Pr(1), two equivalent Pr(2), and two equivalent Pr(3) atoms to form SePr5 square pyramids that share corners with five equivalent Se(1)Pr6 octahedra, corners with four equivalent Se(2)Pr5 square pyramids, corners with four equivalent Se(3)Pr5 square pyramids, edges with three equivalent Se(1)Pr6 octahedra,  an edgeedge with one Se(2)Pr5 square pyramid, edges with four equivalent Se(3)Pr5 square pyramids,  a faceface with one Se(1)Pr6 octahedra, and  a faceface with one Se(2)Pr5 square pyramid. The corner-sharing octahedral tilt angles range from 22-49°. In the third Se site, Se(3) is bonded to one Pr(1), one Pr(2), and three equivalent Pr(3) atoms to form distorted SePr5 square pyramids that share corners with seven equivalent Se(1)Pr6 octahedra, corners with four equivalent Se(2)Pr5 square pyramids, corners with five equivalent Se(3)Pr5 square pyramids,  an edgeedge with one Se(1)Pr6 octahedra, edges with four equivalent Se(2)Pr5 square pyramids, faces with two equivalent Se(1)Pr6 octahedra, and  a faceface with one Se(3)Pr5 square pyramid. The corner-sharing octahedral tilt angles range from 13-54°. is represented by the CIF file [CIF]
data_Pr2Se3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   23.386
_cell_length_b   9.007
_cell_length_c   9.007
_cell_angle_alpha   90.005
_cell_angle_beta   54.716
_cell_angle_gamma   54.716
_symmetry_Int_Tables_number   1
_cell_volume   1094.122
_cell_formula_units_Z   8
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  0.084  0.624  0.374  1.0
  Pr  Pr1  1  0.167  0.250  0.631  1.0
  Pr  Pr2  1  0.338  0.379  0.252  1.0
  Pr  Pr3  1  0.249  0.876  0.126  1.0
  Pr  Pr4  1  0.338  0.108  0.735  1.0
  Pr  Pr5  1  0.167  0.750  0.869  1.0
  Pr  Pr6  1  0.496  0.265  0.621  1.0
  Pr  Pr7  1  0.667  0.369  0.250  1.0
  Pr  Pr8  1  0.584  0.874  0.124  1.0
  Pr  Pr9  1  0.667  0.131  0.750  1.0
  Pr  Pr10  1  0.496  0.749  0.892  1.0
  Pr  Pr11  1  0.749  0.626  0.376  1.0
  Pr  Pr12  1  0.838  0.235  0.608  1.0
  Pr  Pr13  1  0.996  0.392  0.249  1.0
  Pr  Pr14  1  0.996  0.121  0.765  1.0
  Pr  Pr15  1  0.838  0.752  0.879  1.0
  Se  Se16  1  0.050  0.999  0.354  1.0
  Se  Se17  1  0.125  0.489  0.993  1.0
  Se  Se18  1  0.050  0.351  0.496  1.0
  Se  Se19  1  0.283  0.149  0.147  1.0
  Se  Se20  1  0.283  0.501  0.004  1.0
  Se  Se21  1  0.125  0.635  0.631  1.0
  Se  Se22  1  0.384  0.001  0.344  1.0
  Se  Se23  1  0.208  0.865  0.507  1.0
  Se  Se24  1  0.449  0.496  0.999  1.0
  Se  Se25  1  0.384  0.346  0.504  1.0
  Se  Se26  1  0.208  0.011  0.869  1.0
  Se  Se27  1  0.625  0.131  0.135  1.0
  Se  Se28  1  0.625  0.493  0.989  1.0
  Se  Se29  1  0.449  0.656  0.654  1.0
  Se  Se30  1  0.708  0.007  0.365  1.0
  Se  Se31  1  0.550  0.854  0.499  1.0
  Se  Se32  1  0.783  0.504  0.001  1.0
  Se  Se33  1  0.708  0.369  0.511  1.0
  Se  Se34  1  0.550  0.996  0.851  1.0
  Se  Se35  1  0.949  0.154  0.156  1.0
  Se  Se36  1  0.949  0.499  0.996  1.0
  Se  Se37  1  0.783  0.647  0.649  1.0
  Se  Se38  1  0.884  0.844  0.501  1.0
  Se  Se39  1  0.884  0.004  0.846  1.0
[/CIF]
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The crystal structure described by Pr2Se3 crystallizes in the tetragonal I-42d space group. There are three inequivalent Pr sites. In the first Pr site, Pr(1) is bonded to two equivalent Se(2), two equivalent Se(3), and four equivalent Se(1) atoms to form a mixture of distorted edge, face, and corner-sharing PrSe8 hexagonal bipyramids. In the second Pr site, Pr(2) is bonded to two equivalent Se(1), two equivalent Se(3), and four equivalent Se(2) atoms to form a mixture of distorted edge, face, and corner-sharing PrSe8 hexagonal bipyramids. In the third Pr site, Pr(3) is bonded in a 8-coordinate geometry to two equivalent Se(2), three equivalent Se(1), and three equivalent Se(3) atoms. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to one Pr(2), two equivalent Pr(1), and three equivalent Pr(3) atoms to form distorted SePr6 octahedra that share corners with three equivalent Se(1)Pr6 octahedra, corners with five equivalent Se(2)Pr5 square pyramids, corners with seven equivalent Se(3)Pr5 square pyramids, edges with two equivalent Se(1)Pr6 octahedra,  an edgeedge with one Se(3)Pr5 square pyramid, edges with three equivalent Se(2)Pr5 square pyramids, faces with two equivalent Se(1)Pr6 octahedra,  a faceface with one Se(2)Pr5 square pyramid, and faces with two equivalent Se(3)Pr5 square pyramids. The corner-sharing octahedral tilt angles range from 18-49°. In the second Se site, Se(2) is bonded to one Pr(1), two equivalent Pr(2), and two equivalent Pr(3) atoms to form SePr5 square pyramids that share corners with five equivalent Se(1)Pr6 octahedra, corners with four equivalent Se(2)Pr5 square pyramids, corners with four equivalent Se(3)Pr5 square pyramids, edges with three equivalent Se(1)Pr6 octahedra,  an edgeedge with one Se(2)Pr5 square pyramid, edges with four equivalent Se(3)Pr5 square pyramids,  a faceface with one Se(1)Pr6 octahedra, and  a faceface with one Se(2)Pr5 square pyramid. The corner-sharing octahedral tilt angles range from 22-49°. In the third Se site, Se(3) is bonded to one Pr(1), one Pr(2), and three equivalent Pr(3) atoms to form distorted SePr5 square pyramids that share corners with seven equivalent Se(1)Pr6 octahedra, corners with four equivalent Se(2)Pr5 square pyramids, corners with five equivalent Se(3)Pr5 square pyramids,  an edgeedge with one Se(1)Pr6 octahedra, edges with four equivalent Se(2)Pr5 square pyramids, faces with two equivalent Se(1)Pr6 octahedra, and  a faceface with one Se(3)Pr5 square pyramid. The corner-sharing octahedral tilt angles range from 13-54°. is represented by the CIF file [CIF]
data_Pr2Se3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   23.386
_cell_length_b   9.007
_cell_length_c   9.007
_cell_angle_alpha   90.005
_cell_angle_beta   54.716
_cell_angle_gamma   54.716
_symmetry_Int_Tables_number   1
_cell_volume   1094.122
_cell_formula_units_Z   8
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  0.084  0.624  0.374  1.0
  Pr  Pr1  1  0.167  0.250  0.631  1.0
  Pr  Pr2  1  0.338  0.379  0.252  1.0
  Pr  Pr3  1  0.249  0.876  0.126  1.0
  Pr  Pr4  1  0.338  0.108  0.735  1.0
  Pr  Pr5  1  0.167  0.750  0.869  1.0
  Pr  Pr6  1  0.496  0.265  0.621  1.0
  Pr  Pr7  1  0.667  0.369  0.250  1.0
  Pr  Pr8  1  0.584  0.874  0.124  1.0
  Pr  Pr9  1  0.667  0.131  0.750  1.0
  Pr  Pr10  1  0.496  0.749  0.892  1.0
  Pr  Pr11  1  0.749  0.626  0.376  1.0
  Pr  Pr12  1  0.838  0.235  0.608  1.0
  Pr  Pr13  1  0.996  0.392  0.249  1.0
  Pr  Pr14  1  0.996  0.121  0.765  1.0
  Pr  Pr15  1  0.838  0.752  0.879  1.0
  Se  Se16  1  0.050  0.999  0.354  1.0
  Se  Se17  1  0.125  0.489  0.993  1.0
  Se  Se18  1  0.050  0.351  0.496  1.0
  Se  Se19  1  0.283  0.149  0.147  1.0
  Se  Se20  1  0.283  0.501  0.004  1.0
  Se  Se21  1  0.125  0.635  0.631  1.0
  Se  Se22  1  0.384  0.001  0.344  1.0
  Se  Se23  1  0.208  0.865  0.507  1.0
  Se  Se24  1  0.449  0.496  0.999  1.0
  Se  Se25  1  0.384  0.346  0.504  1.0
  Se  Se26  1  0.208  0.011  0.869  1.0
  Se  Se27  1  0.625  0.131  0.135  1.0
  Se  Se28  1  0.625  0.493  0.989  1.0
  Se  Se29  1  0.449  0.656  0.654  1.0
  Se  Se30  1  0.708  0.007  0.365  1.0
  Se  Se31  1  0.550  0.854  0.499  1.0
  Se  Se32  1  0.783  0.504  0.001  1.0
  Se  Se33  1  0.708  0.369  0.511  1.0
  Se  Se34  1  0.550  0.996  0.851  1.0
  Se  Se35  1  0.949  0.154  0.156  1.0
  Se  Se36  1  0.949  0.499  0.996  1.0
  Se  Se37  1  0.783  0.647  0.649  1.0
  Se  Se38  1  0.884  0.844  0.501  1.0
  Se  Se39  1  0.884  0.004  0.846  1.0
[/CIF]
.