The material described by YSeF crystallizes in the monoclinic P2_1/m space group. There are four inequivalent Y sites. In the first Y site, Y(1) is bonded to one Se(1), two equivalent Se(3), and three equivalent Se(2) atoms to form YSe6 octahedra that share corners with four equivalent Y(2)Se2F6 hexagonal bipyramids, corners with two equivalent Y(3)Se4F3 pentagonal bipyramids, edges with four equivalent Y(1)Se6 octahedra, and edges with two equivalent Y(4)Se4F3 pentagonal bipyramids. In the second Y site, Y(2) is bonded to one Se(1), one Se(2), one F(1), two equivalent F(3), and three equivalent F(4) atoms to form YSe2F6 hexagonal bipyramids that share corners with four equivalent Y(1)Se6 octahedra, corners with two equivalent Y(4)Se4F3 pentagonal bipyramids, edges with four equivalent Y(2)Se2F6 hexagonal bipyramids, and edges with two equivalent Y(3)Se4F3 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 55-59°. In the third Y site, Y(3) is bonded to one Se(3), three equivalent Se(4), one F(3), and two equivalent F(1) atoms to form distorted YSe4F3 pentagonal bipyramids that share corners with two equivalent Y(1)Se6 octahedra, corners with four equivalent Y(4)Se4F3 pentagonal bipyramids, edges with two equivalent Y(2)Se2F6 hexagonal bipyramids, and edges with four equivalent Y(3)Se4F3 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 59°. In the fourth Y site, Y(4) is bonded to one Se(3), one Se(4), two equivalent Se(1), and three equivalent F(2) atoms to form distorted YSe4F3 pentagonal bipyramids that share corners with two equivalent Y(2)Se2F6 hexagonal bipyramids, corners with four equivalent Y(3)Se4F3 pentagonal bipyramids, edges with two equivalent Y(1)Se6 octahedra, and edges with four equivalent Y(4)Se4F3 pentagonal bipyramids. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded in a rectangular see-saw-like geometry to one Y(1), one Y(2), and two equivalent Y(4) atoms. In the second Se site, Se(2) is bonded in a rectangular see-saw-like geometry to one Y(2) and three equivalent Y(1) atoms. In the third Se site, Se(3) is bonded in a rectangular see-saw-like geometry to one Y(3), one Y(4), and two equivalent Y(1) atoms. In the fourth Se site, Se(4) is bonded in a rectangular see-saw-like geometry to one Y(4) and three equivalent Y(3) atoms. There are four inequivalent F sites. In the first F site, F(1) is bonded in a trigonal planar geometry to one Y(2) and two equivalent Y(3) atoms. In the second F site, F(2) is bonded in a trigonal planar geometry to three equivalent Y(4) atoms. In the third F site, F(3) is bonded in a trigonal planar geometry to one Y(3) and two equivalent Y(2) atoms. In the fourth F site, F(4) is bonded in a trigonal planar geometry to three equivalent Y(2) atoms. is represented by the CIF file [CIF]
data_YSeF
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.094
_cell_length_b   9.980
_cell_length_c   13.069
_cell_angle_alpha   74.935
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   515.664
_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  0.250  0.544  0.127  1.0
  Y  Y1  1  0.750  0.456  0.873  1.0
  Y  Y2  1  0.250  0.039  0.121  1.0
  Y  Y3  1  0.750  0.961  0.879  1.0
  Y  Y4  1  0.250  0.882  0.638  1.0
  Y  Y5  1  0.750  0.118  0.362  1.0
  Y  Y6  1  0.250  0.377  0.614  1.0
  Y  Y7  1  0.750  0.623  0.386  1.0
  Se  Se8  1  0.250  0.758  0.235  1.0
  Se  Se9  1  0.750  0.242  0.765  1.0
  Se  Se10  1  0.250  0.329  0.019  1.0
  Se  Se11  1  0.750  0.671  0.981  1.0
  Se  Se12  1  0.250  0.585  0.730  1.0
  Se  Se13  1  0.750  0.415  0.270  1.0
  Se  Se14  1  0.250  0.160  0.512  1.0
  Se  Se15  1  0.750  0.840  0.488  1.0
  F  F16  1  0.250  0.100  0.291  1.0
  F  F17  1  0.750  0.900  0.709  1.0
  F  F18  1  0.250  0.552  0.456  1.0
  F  F19  1  0.750  0.448  0.544  1.0
  F  F20  1  0.250  0.932  0.797  1.0
  F  F21  1  0.750  0.068  0.203  1.0
  F  F22  1  0.250  0.985  0.961  1.0
  F  F23  1  0.750  0.015  0.039  1.0
[/CIF]
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The material described by YSeF crystallizes in the monoclinic P2_1/m space group. There are four inequivalent Y sites. In the first Y site, Y(1) is bonded to one Se(1), two equivalent Se(3), and three equivalent Se(2) atoms to form YSe6 octahedra that share corners with four equivalent Y(2)Se2F6 hexagonal bipyramids, corners with two equivalent Y(3)Se4F3 pentagonal bipyramids, edges with four equivalent Y(1)Se6 octahedra, and edges with two equivalent Y(4)Se4F3 pentagonal bipyramids. In the second Y site, Y(2) is bonded to one Se(1), one Se(2), one F(1), two equivalent F(3), and three equivalent F(4) atoms to form YSe2F6 hexagonal bipyramids that share corners with four equivalent Y(1)Se6 octahedra, corners with two equivalent Y(4)Se4F3 pentagonal bipyramids, edges with four equivalent Y(2)Se2F6 hexagonal bipyramids, and edges with two equivalent Y(3)Se4F3 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 55-59°. In the third Y site, Y(3) is bonded to one Se(3), three equivalent Se(4), one F(3), and two equivalent F(1) atoms to form distorted YSe4F3 pentagonal bipyramids that share corners with two equivalent Y(1)Se6 octahedra, corners with four equivalent Y(4)Se4F3 pentagonal bipyramids, edges with two equivalent Y(2)Se2F6 hexagonal bipyramids, and edges with four equivalent Y(3)Se4F3 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 59°. In the fourth Y site, Y(4) is bonded to one Se(3), one Se(4), two equivalent Se(1), and three equivalent F(2) atoms to form distorted YSe4F3 pentagonal bipyramids that share corners with two equivalent Y(2)Se2F6 hexagonal bipyramids, corners with four equivalent Y(3)Se4F3 pentagonal bipyramids, edges with two equivalent Y(1)Se6 octahedra, and edges with four equivalent Y(4)Se4F3 pentagonal bipyramids. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded in a rectangular see-saw-like geometry to one Y(1), one Y(2), and two equivalent Y(4) atoms. In the second Se site, Se(2) is bonded in a rectangular see-saw-like geometry to one Y(2) and three equivalent Y(1) atoms. In the third Se site, Se(3) is bonded in a rectangular see-saw-like geometry to one Y(3), one Y(4), and two equivalent Y(1) atoms. In the fourth Se site, Se(4) is bonded in a rectangular see-saw-like geometry to one Y(4) and three equivalent Y(3) atoms. There are four inequivalent F sites. In the first F site, F(1) is bonded in a trigonal planar geometry to one Y(2) and two equivalent Y(3) atoms. In the second F site, F(2) is bonded in a trigonal planar geometry to three equivalent Y(4) atoms. In the third F site, F(3) is bonded in a trigonal planar geometry to one Y(3) and two equivalent Y(2) atoms. In the fourth F site, F(4) is bonded in a trigonal planar geometry to three equivalent Y(2) atoms. is represented by the CIF file [CIF]
data_YSeF
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.094
_cell_length_b   9.980
_cell_length_c   13.069
_cell_angle_alpha   74.935
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   515.664
_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  0.250  0.544  0.127  1.0
  Y  Y1  1  0.750  0.456  0.873  1.0
  Y  Y2  1  0.250  0.039  0.121  1.0
  Y  Y3  1  0.750  0.961  0.879  1.0
  Y  Y4  1  0.250  0.882  0.638  1.0
  Y  Y5  1  0.750  0.118  0.362  1.0
  Y  Y6  1  0.250  0.377  0.614  1.0
  Y  Y7  1  0.750  0.623  0.386  1.0
  Se  Se8  1  0.250  0.758  0.235  1.0
  Se  Se9  1  0.750  0.242  0.765  1.0
  Se  Se10  1  0.250  0.329  0.019  1.0
  Se  Se11  1  0.750  0.671  0.981  1.0
  Se  Se12  1  0.250  0.585  0.730  1.0
  Se  Se13  1  0.750  0.415  0.270  1.0
  Se  Se14  1  0.250  0.160  0.512  1.0
  Se  Se15  1  0.750  0.840  0.488  1.0
  F  F16  1  0.250  0.100  0.291  1.0
  F  F17  1  0.750  0.900  0.709  1.0
  F  F18  1  0.250  0.552  0.456  1.0
  F  F19  1  0.750  0.448  0.544  1.0
  F  F20  1  0.250  0.932  0.797  1.0
  F  F21  1  0.750  0.068  0.203  1.0
  F  F22  1  0.250  0.985  0.961  1.0
  F  F23  1  0.750  0.015  0.039  1.0
[/CIF]
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