The structure described by Pm2Se3 is Stibnite structured and crystallizes in the orthorhombic Pnma space group. There are two inequivalent Pm sites. In the first Pm site, Pm(1) is bonded in a 8-coordinate geometry to two equivalent Se(1), three equivalent Se(2), and three equivalent Se(3) atoms. In the second Pm site, Pm(2) is bonded to two equivalent Se(2), two equivalent Se(3), and three equivalent Se(1) atoms to form a mixture of distorted corner and edge-sharing PmSe7 pentagonal bipyramids. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Pm(1) and three equivalent Pm(2) atoms to form a mixture of corner and edge-sharing SePm5 square pyramids. In the second Se site, Se(2) is bonded to two equivalent Pm(2) and three equivalent Pm(1) atoms to form a mixture of distorted corner and edge-sharing SePm5 trigonal bipyramids. In the third Se site, Se(3) is bonded in a 5-coordinate geometry to two equivalent Pm(2) and three equivalent Pm(1) atoms. is represented by the CIF file [CIF]
data_Pm2Se3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.142
_cell_length_b   11.156
_cell_length_c   11.413
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   527.364
_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
  Pm  Pm0  1  0.250  0.997  0.693  1.0
  Pm  Pm1  1  0.750  0.003  0.307  1.0
  Pm  Pm2  1  0.750  0.497  0.807  1.0
  Pm  Pm3  1  0.250  0.503  0.193  1.0
  Pm  Pm4  1  0.250  0.313  0.511  1.0
  Pm  Pm5  1  0.750  0.687  0.489  1.0
  Pm  Pm6  1  0.750  0.813  0.989  1.0
  Pm  Pm7  1  0.250  0.187  0.011  1.0
  Se  Se8  1  0.750  0.056  0.880  1.0
  Se  Se9  1  0.250  0.944  0.120  1.0
  Se  Se10  1  0.250  0.556  0.620  1.0
  Se  Se11  1  0.750  0.444  0.380  1.0
  Se  Se12  1  0.250  0.874  0.455  1.0
  Se  Se13  1  0.750  0.126  0.545  1.0
  Se  Se14  1  0.750  0.374  0.045  1.0
  Se  Se15  1  0.250  0.626  0.955  1.0
  Se  Se16  1  0.250  0.302  0.772  1.0
  Se  Se17  1  0.750  0.698  0.228  1.0
  Se  Se18  1  0.750  0.802  0.728  1.0
  Se  Se19  1  0.250  0.198  0.272  1.0
[/CIF]
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The structure described by Pm2Se3 is Stibnite structured and crystallizes in the orthorhombic Pnma space group. There are two inequivalent Pm sites. In the first Pm site, Pm(1) is bonded in a 8-coordinate geometry to two equivalent Se(1), three equivalent Se(2), and three equivalent Se(3) atoms. In the second Pm site, Pm(2) is bonded to two equivalent Se(2), two equivalent Se(3), and three equivalent Se(1) atoms to form a mixture of distorted corner and edge-sharing PmSe7 pentagonal bipyramids. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Pm(1) and three equivalent Pm(2) atoms to form a mixture of corner and edge-sharing SePm5 square pyramids. In the second Se site, Se(2) is bonded to two equivalent Pm(2) and three equivalent Pm(1) atoms to form a mixture of distorted corner and edge-sharing SePm5 trigonal bipyramids. In the third Se site, Se(3) is bonded in a 5-coordinate geometry to two equivalent Pm(2) and three equivalent Pm(1) atoms. is represented by the CIF file [CIF]
data_Pm2Se3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.142
_cell_length_b   11.156
_cell_length_c   11.413
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   527.364
_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
  Pm  Pm0  1  0.250  0.997  0.693  1.0
  Pm  Pm1  1  0.750  0.003  0.307  1.0
  Pm  Pm2  1  0.750  0.497  0.807  1.0
  Pm  Pm3  1  0.250  0.503  0.193  1.0
  Pm  Pm4  1  0.250  0.313  0.511  1.0
  Pm  Pm5  1  0.750  0.687  0.489  1.0
  Pm  Pm6  1  0.750  0.813  0.989  1.0
  Pm  Pm7  1  0.250  0.187  0.011  1.0
  Se  Se8  1  0.750  0.056  0.880  1.0
  Se  Se9  1  0.250  0.944  0.120  1.0
  Se  Se10  1  0.250  0.556  0.620  1.0
  Se  Se11  1  0.750  0.444  0.380  1.0
  Se  Se12  1  0.250  0.874  0.455  1.0
  Se  Se13  1  0.750  0.126  0.545  1.0
  Se  Se14  1  0.750  0.374  0.045  1.0
  Se  Se15  1  0.250  0.626  0.955  1.0
  Se  Se16  1  0.250  0.302  0.772  1.0
  Se  Se17  1  0.750  0.698  0.228  1.0
  Se  Se18  1  0.750  0.802  0.728  1.0
  Se  Se19  1  0.250  0.198  0.272  1.0
[/CIF]
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