The material described by Y2Se3 crystallizes in the tetragonal I-42d space group. There are three inequivalent Y sites. In the first Y site, Y(1) is bonded in a 8-coordinate geometry to two equivalent Se(2), two equivalent Se(3), and four equivalent Se(1) atoms. In the second Y site, Y(2) is bonded in a 8-coordinate geometry to two equivalent Se(1), two equivalent Se(3), and four equivalent Se(2) atoms. In the third Y site, Y(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 Y(2), two equivalent Y(1), and three equivalent Y(3) atoms to form distorted SeY6 octahedra that share corners with three equivalent Se(1)Y6 octahedra, corners with five equivalent Se(2)Y5 square pyramids, corners with seven equivalent Se(3)Y5 square pyramids, edges with two equivalent Se(1)Y6 octahedra,  an edgeedge with one Se(3)Y5 square pyramid, edges with three equivalent Se(2)Y5 square pyramids, faces with two equivalent Se(1)Y6 octahedra,  a faceface with one Se(2)Y5 square pyramid, and faces with two equivalent Se(3)Y5 square pyramids. The corner-sharing octahedral tilt angles range from 18-50°. In the second Se site, Se(2) is bonded to one Y(1), two equivalent Y(2), and two equivalent Y(3) atoms to form distorted SeY5 square pyramids that share corners with five equivalent Se(1)Y6 octahedra, corners with four equivalent Se(2)Y5 square pyramids, corners with four equivalent Se(3)Y5 square pyramids, edges with three equivalent Se(1)Y6 octahedra,  an edgeedge with one Se(2)Y5 square pyramid, edges with four equivalent Se(3)Y5 square pyramids,  a faceface with one Se(1)Y6 octahedra, and  a faceface with one Se(2)Y5 square pyramid. The corner-sharing octahedral tilt angles range from 23-49°. In the third Se site, Se(3) is bonded to one Y(1), one Y(2), and three equivalent Y(3) atoms to form distorted SeY5 square pyramids that share corners with seven equivalent Se(1)Y6 octahedra, corners with four equivalent Se(2)Y5 square pyramids, corners with five equivalent Se(3)Y5 square pyramids,  an edgeedge with one Se(1)Y6 octahedra, edges with four equivalent Se(2)Y5 square pyramids, faces with two equivalent Se(1)Y6 octahedra, and  a faceface with one Se(3)Y5 square pyramid. The corner-sharing octahedral tilt angles range from 15-53°. is represented by the CIF card [CIF]
data_Y2Se3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   14.454
_cell_length_b   14.454
_cell_length_c   14.454
_cell_angle_alpha   144.881
_cell_angle_beta   144.881
_cell_angle_gamma   50.512
_symmetry_Int_Tables_number   1
_cell_volume   994.323
_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
  Y  Y0  1  0.583  0.083  0.500  1.0
  Y  Y1  1  0.875  0.507  0.132  1.0
  Y  Y2  1  0.577  0.469  0.625  1.0
  Y  Y3  1  0.167  0.167  0.000  1.0
  Y  Y4  1  0.844  0.952  0.375  1.0
  Y  Y5  1  0.375  0.743  0.868  1.0
  Y  Y6  1  0.531  0.156  0.108  1.0
  Y  Y7  1  0.257  0.125  0.632  1.0
  Y  Y8  1  0.833  0.833  0.000  1.0
  Y  Y9  1  0.048  0.423  0.892  1.0
  Y  Y10  1  0.493  0.625  0.368  1.0
  Y  Y11  1  0.917  0.417  0.500  1.0
  Y  Y12  1  0.219  0.827  0.125  1.0
  Y  Y13  1  0.906  0.781  0.608  1.0
  Y  Y14  1  0.702  0.094  0.875  1.0
  Y  Y15  1  0.173  0.298  0.392  1.0
  Se  Se16  1  0.245  0.999  0.112  1.0
  Se  Se17  1  0.675  0.788  0.253  1.0
  Se  Se18  1  0.887  0.132  0.888  1.0
  Se  Se19  1  0.863  0.251  0.746  1.0
  Se  Se20  1  0.505  0.118  0.254  1.0
  Se  Se21  1  0.534  0.422  0.747  1.0
  Se  Se22  1  0.908  0.653  0.096  1.0
  Se  Se23  1  0.216  0.462  0.387  1.0
  Se  Se24  1  0.347  0.443  0.255  1.0
  Se  Se25  1  0.557  0.812  0.904  1.0
  Se  Se26  1  0.075  0.828  0.613  1.0
  Se  Se27  1  0.538  0.925  0.753  1.0
  Se  Se28  1  0.172  0.784  0.247  1.0
  Se  Se29  1  0.188  0.092  0.745  1.0
  Se  Se30  1  0.578  0.325  0.113  1.0
  Se  Se31  1  0.882  0.137  0.388  1.0
  Se  Se32  1  0.001  0.113  0.246  1.0
  Se  Se33  1  0.212  0.466  0.887  1.0
  Se  Se34  1  0.749  0.495  0.612  1.0
  Se  Se35  1  0.193  0.597  0.755  1.0
  Se  Se36  1  0.842  0.438  0.245  1.0
  Se  Se37  1  0.868  0.755  0.754  1.0
  Se  Se38  1  0.562  0.807  0.404  1.0
  Se  Se39  1  0.403  0.158  0.596  1.0
[/CIF]
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The material described by Y2Se3 crystallizes in the tetragonal I-42d space group. There are three inequivalent Y sites. In the first Y site, Y(1) is bonded in a 8-coordinate geometry to two equivalent Se(2), two equivalent Se(3), and four equivalent Se(1) atoms. In the second Y site, Y(2) is bonded in a 8-coordinate geometry to two equivalent Se(1), two equivalent Se(3), and four equivalent Se(2) atoms. In the third Y site, Y(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 Y(2), two equivalent Y(1), and three equivalent Y(3) atoms to form distorted SeY6 octahedra that share corners with three equivalent Se(1)Y6 octahedra, corners with five equivalent Se(2)Y5 square pyramids, corners with seven equivalent Se(3)Y5 square pyramids, edges with two equivalent Se(1)Y6 octahedra,  an edgeedge with one Se(3)Y5 square pyramid, edges with three equivalent Se(2)Y5 square pyramids, faces with two equivalent Se(1)Y6 octahedra,  a faceface with one Se(2)Y5 square pyramid, and faces with two equivalent Se(3)Y5 square pyramids. The corner-sharing octahedral tilt angles range from 18-50°. In the second Se site, Se(2) is bonded to one Y(1), two equivalent Y(2), and two equivalent Y(3) atoms to form distorted SeY5 square pyramids that share corners with five equivalent Se(1)Y6 octahedra, corners with four equivalent Se(2)Y5 square pyramids, corners with four equivalent Se(3)Y5 square pyramids, edges with three equivalent Se(1)Y6 octahedra,  an edgeedge with one Se(2)Y5 square pyramid, edges with four equivalent Se(3)Y5 square pyramids,  a faceface with one Se(1)Y6 octahedra, and  a faceface with one Se(2)Y5 square pyramid. The corner-sharing octahedral tilt angles range from 23-49°. In the third Se site, Se(3) is bonded to one Y(1), one Y(2), and three equivalent Y(3) atoms to form distorted SeY5 square pyramids that share corners with seven equivalent Se(1)Y6 octahedra, corners with four equivalent Se(2)Y5 square pyramids, corners with five equivalent Se(3)Y5 square pyramids,  an edgeedge with one Se(1)Y6 octahedra, edges with four equivalent Se(2)Y5 square pyramids, faces with two equivalent Se(1)Y6 octahedra, and  a faceface with one Se(3)Y5 square pyramid. The corner-sharing octahedral tilt angles range from 15-53°. is represented by the CIF card [CIF]
data_Y2Se3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   14.454
_cell_length_b   14.454
_cell_length_c   14.454
_cell_angle_alpha   144.881
_cell_angle_beta   144.881
_cell_angle_gamma   50.512
_symmetry_Int_Tables_number   1
_cell_volume   994.323
_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
  Y  Y0  1  0.583  0.083  0.500  1.0
  Y  Y1  1  0.875  0.507  0.132  1.0
  Y  Y2  1  0.577  0.469  0.625  1.0
  Y  Y3  1  0.167  0.167  0.000  1.0
  Y  Y4  1  0.844  0.952  0.375  1.0
  Y  Y5  1  0.375  0.743  0.868  1.0
  Y  Y6  1  0.531  0.156  0.108  1.0
  Y  Y7  1  0.257  0.125  0.632  1.0
  Y  Y8  1  0.833  0.833  0.000  1.0
  Y  Y9  1  0.048  0.423  0.892  1.0
  Y  Y10  1  0.493  0.625  0.368  1.0
  Y  Y11  1  0.917  0.417  0.500  1.0
  Y  Y12  1  0.219  0.827  0.125  1.0
  Y  Y13  1  0.906  0.781  0.608  1.0
  Y  Y14  1  0.702  0.094  0.875  1.0
  Y  Y15  1  0.173  0.298  0.392  1.0
  Se  Se16  1  0.245  0.999  0.112  1.0
  Se  Se17  1  0.675  0.788  0.253  1.0
  Se  Se18  1  0.887  0.132  0.888  1.0
  Se  Se19  1  0.863  0.251  0.746  1.0
  Se  Se20  1  0.505  0.118  0.254  1.0
  Se  Se21  1  0.534  0.422  0.747  1.0
  Se  Se22  1  0.908  0.653  0.096  1.0
  Se  Se23  1  0.216  0.462  0.387  1.0
  Se  Se24  1  0.347  0.443  0.255  1.0
  Se  Se25  1  0.557  0.812  0.904  1.0
  Se  Se26  1  0.075  0.828  0.613  1.0
  Se  Se27  1  0.538  0.925  0.753  1.0
  Se  Se28  1  0.172  0.784  0.247  1.0
  Se  Se29  1  0.188  0.092  0.745  1.0
  Se  Se30  1  0.578  0.325  0.113  1.0
  Se  Se31  1  0.882  0.137  0.388  1.0
  Se  Se32  1  0.001  0.113  0.246  1.0
  Se  Se33  1  0.212  0.466  0.887  1.0
  Se  Se34  1  0.749  0.495  0.612  1.0
  Se  Se35  1  0.193  0.597  0.755  1.0
  Se  Se36  1  0.842  0.438  0.245  1.0
  Se  Se37  1  0.868  0.755  0.754  1.0
  Se  Se38  1  0.562  0.807  0.404  1.0
  Se  Se39  1  0.403  0.158  0.596  1.0
[/CIF]
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