The material structure described by Y3Se4 crystallizes in the monoclinic C2/m space group. There are six inequivalent Y sites. In the first Y site, Y(1) is bonded to one Se(1), one Se(2), one Se(3), one Se(4), one Se(5), and one Se(6) atom to form a mixture of edge and corner-sharing YSe6 octahedra. The corner-sharing octahedral tilt angles range from 1-4°. In the second Y site, Y(2) is bonded to two equivalent Se(3) and four equivalent Se(1) atoms to form a mixture of edge and corner-sharing YSe6 octahedra. The corner-sharing octahedral tilt angles are 2°. In the third Y site, Y(3) is bonded to one Se(3), one Se(6), two equivalent Se(1), and two equivalent Se(4) atoms to form a mixture of edge and corner-sharing YSe6 octahedra. The corner-sharing octahedral tilt angles are 2°. In the fourth Y site, Y(4) is bonded to two equivalent Se(1), two equivalent Se(2), and two equivalent Se(3) atoms to form a mixture of edge and corner-sharing YSe6 octahedra. The corner-sharing octahedral tilt angles are 2°. In the fifth Y site, Y(5) is bonded to two equivalent Se(5) and four equivalent Se(4) atoms to form edge-sharing YSe6 octahedra. In the sixth Y site, Y(6) is bonded to two equivalent Se(4), two equivalent Se(5), and two equivalent Se(6) atoms to form a mixture of edge and corner-sharing YSe6 octahedra. The corner-sharing octahedral tilt angles range from 1-4°. There are six inequivalent Se sites. In the first Se site, Se(6) is bonded to one Y(3), two equivalent Y(1), and two equivalent Y(6) atoms to form SeY5 square pyramids that share corners with three equivalent Se(3)Y6 octahedra, corners with two equivalent Se(6)Y5 square pyramids, and edges with three equivalent Se(5)Y5 square pyramids. The corner-sharing octahedral tilt angles are 4°. In the second Se site, Se(1) is bonded in a rectangular see-saw-like geometry to one Y(1), one Y(2), one Y(3), and one Y(4) atom. In the third Se site, Se(2) is bonded in a rectangular see-saw-like geometry to two equivalent Y(1) and two equivalent Y(4) atoms. In the fourth Se site, Se(3) is bonded to one Y(2), one Y(3), two equivalent Y(1), and two equivalent Y(4) atoms to form SeY6 octahedra that share corners with three equivalent Se(3)Y6 octahedra, corners with three equivalent Se(6)Y5 square pyramids, and  an edgeedge with one Se(5)Y5 square pyramid. The corner-sharing octahedra are not tilted. In the fifth Se site, Se(4) is bonded in a rectangular see-saw-like geometry to one Y(1), one Y(3), one Y(5), and one Y(6) atom. In the sixth Se site, Se(5) is bonded to one Y(5), two equivalent Y(1), and two equivalent Y(6) atoms to form SeY5 square pyramids that share corners with three equivalent Se(5)Y5 square pyramids,  an edgeedge with one Se(3)Y6 octahedra, and edges with three equivalent Se(6)Y5 square pyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_Y3Se4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.100
_cell_length_b   8.160
_cell_length_c   16.148
_cell_angle_alpha   59.643
_cell_angle_beta   60.218
_cell_angle_gamma   59.753
_symmetry_Int_Tables_number   1
_cell_volume   752.505
_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
  Y  Y0  1  0.995  0.990  0.004  1.0
  Y  Y1  1  0.995  0.507  0.004  1.0
  Y  Y2  1  0.000  0.000  0.250  1.0
  Y  Y3  1  0.486  0.501  0.006  1.0
  Y  Y4  1  0.500  0.000  0.250  1.0
  Y  Y5  1  0.005  0.493  0.496  1.0
  Y  Y6  1  0.500  0.500  0.250  1.0
  Y  Y7  1  0.005  0.010  0.496  1.0
  Y  Y8  1  0.000  0.500  0.750  1.0
  Y  Y9  1  0.514  0.499  0.494  1.0
  Y  Y10  1  0.500  0.000  0.750  1.0
  Y  Y11  1  0.500  0.500  0.750  1.0
  Se  Se12  1  0.248  0.249  0.125  1.0
  Se  Se13  1  0.248  0.754  0.125  1.0
  Se  Se14  1  0.256  0.247  0.375  1.0
  Se  Se15  1  0.251  0.749  0.375  1.0
  Se  Se16  1  0.254  0.257  0.624  1.0
  Se  Se17  1  0.749  0.251  0.125  1.0
  Se  Se18  1  0.752  0.246  0.375  1.0
  Se  Se19  1  0.249  0.248  0.877  1.0
  Se  Se20  1  0.254  0.741  0.624  1.0
  Se  Se21  1  0.744  0.753  0.125  1.0
  Se  Se22  1  0.244  0.756  0.872  1.0
  Se  Se23  1  0.752  0.751  0.375  1.0
  Se  Se24  1  0.756  0.244  0.628  1.0
  Se  Se25  1  0.746  0.259  0.876  1.0
  Se  Se26  1  0.751  0.752  0.623  1.0
  Se  Se27  1  0.746  0.743  0.876  1.0
[/CIF]
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The material structure described by Y3Se4 crystallizes in the monoclinic C2/m space group. There are six inequivalent Y sites. In the first Y site, Y(1) is bonded to one Se(1), one Se(2), one Se(3), one Se(4), one Se(5), and one Se(6) atom to form a mixture of edge and corner-sharing YSe6 octahedra. The corner-sharing octahedral tilt angles range from 1-4°. In the second Y site, Y(2) is bonded to two equivalent Se(3) and four equivalent Se(1) atoms to form a mixture of edge and corner-sharing YSe6 octahedra. The corner-sharing octahedral tilt angles are 2°. In the third Y site, Y(3) is bonded to one Se(3), one Se(6), two equivalent Se(1), and two equivalent Se(4) atoms to form a mixture of edge and corner-sharing YSe6 octahedra. The corner-sharing octahedral tilt angles are 2°. In the fourth Y site, Y(4) is bonded to two equivalent Se(1), two equivalent Se(2), and two equivalent Se(3) atoms to form a mixture of edge and corner-sharing YSe6 octahedra. The corner-sharing octahedral tilt angles are 2°. In the fifth Y site, Y(5) is bonded to two equivalent Se(5) and four equivalent Se(4) atoms to form edge-sharing YSe6 octahedra. In the sixth Y site, Y(6) is bonded to two equivalent Se(4), two equivalent Se(5), and two equivalent Se(6) atoms to form a mixture of edge and corner-sharing YSe6 octahedra. The corner-sharing octahedral tilt angles range from 1-4°. There are six inequivalent Se sites. In the first Se site, Se(6) is bonded to one Y(3), two equivalent Y(1), and two equivalent Y(6) atoms to form SeY5 square pyramids that share corners with three equivalent Se(3)Y6 octahedra, corners with two equivalent Se(6)Y5 square pyramids, and edges with three equivalent Se(5)Y5 square pyramids. The corner-sharing octahedral tilt angles are 4°. In the second Se site, Se(1) is bonded in a rectangular see-saw-like geometry to one Y(1), one Y(2), one Y(3), and one Y(4) atom. In the third Se site, Se(2) is bonded in a rectangular see-saw-like geometry to two equivalent Y(1) and two equivalent Y(4) atoms. In the fourth Se site, Se(3) is bonded to one Y(2), one Y(3), two equivalent Y(1), and two equivalent Y(4) atoms to form SeY6 octahedra that share corners with three equivalent Se(3)Y6 octahedra, corners with three equivalent Se(6)Y5 square pyramids, and  an edgeedge with one Se(5)Y5 square pyramid. The corner-sharing octahedra are not tilted. In the fifth Se site, Se(4) is bonded in a rectangular see-saw-like geometry to one Y(1), one Y(3), one Y(5), and one Y(6) atom. In the sixth Se site, Se(5) is bonded to one Y(5), two equivalent Y(1), and two equivalent Y(6) atoms to form SeY5 square pyramids that share corners with three equivalent Se(5)Y5 square pyramids,  an edgeedge with one Se(3)Y6 octahedra, and edges with three equivalent Se(6)Y5 square pyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_Y3Se4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.100
_cell_length_b   8.160
_cell_length_c   16.148
_cell_angle_alpha   59.643
_cell_angle_beta   60.218
_cell_angle_gamma   59.753
_symmetry_Int_Tables_number   1
_cell_volume   752.505
_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
  Y  Y0  1  0.995  0.990  0.004  1.0
  Y  Y1  1  0.995  0.507  0.004  1.0
  Y  Y2  1  0.000  0.000  0.250  1.0
  Y  Y3  1  0.486  0.501  0.006  1.0
  Y  Y4  1  0.500  0.000  0.250  1.0
  Y  Y5  1  0.005  0.493  0.496  1.0
  Y  Y6  1  0.500  0.500  0.250  1.0
  Y  Y7  1  0.005  0.010  0.496  1.0
  Y  Y8  1  0.000  0.500  0.750  1.0
  Y  Y9  1  0.514  0.499  0.494  1.0
  Y  Y10  1  0.500  0.000  0.750  1.0
  Y  Y11  1  0.500  0.500  0.750  1.0
  Se  Se12  1  0.248  0.249  0.125  1.0
  Se  Se13  1  0.248  0.754  0.125  1.0
  Se  Se14  1  0.256  0.247  0.375  1.0
  Se  Se15  1  0.251  0.749  0.375  1.0
  Se  Se16  1  0.254  0.257  0.624  1.0
  Se  Se17  1  0.749  0.251  0.125  1.0
  Se  Se18  1  0.752  0.246  0.375  1.0
  Se  Se19  1  0.249  0.248  0.877  1.0
  Se  Se20  1  0.254  0.741  0.624  1.0
  Se  Se21  1  0.744  0.753  0.125  1.0
  Se  Se22  1  0.244  0.756  0.872  1.0
  Se  Se23  1  0.752  0.751  0.375  1.0
  Se  Se24  1  0.756  0.244  0.628  1.0
  Se  Se25  1  0.746  0.259  0.876  1.0
  Se  Se26  1  0.751  0.752  0.623  1.0
  Se  Se27  1  0.746  0.743  0.876  1.0
[/CIF]
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