The structure described by PmSe3 crystallizes in the tetragonal I4/mmm space group. Pm(1) is bonded to four equivalent Se(2) and eight equivalent Se(1) atoms to form distorted PmSe12 cuboctahedra that share corners with four equivalent Pm(1)Se12 cuboctahedra, corners with sixteen equivalent Se(1)Pm4Se4 hexagonal bipyramids, edges with eight equivalent Pm(1)Se12 cuboctahedra, edges with eight equivalent Se(1)Pm4Se4 hexagonal bipyramids, and faces with four equivalent Pm(1)Se12 cuboctahedra. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to four equivalent Pm(1) and four equivalent Se(1) atoms to form distorted SePm4Se4 hexagonal bipyramids that share corners with eight equivalent Pm(1)Se12 cuboctahedra, corners with sixteen equivalent Se(1)Pm4Se4 hexagonal bipyramids, edges with four equivalent Pm(1)Se12 cuboctahedra, edges with six equivalent Se(1)Pm4Se4 hexagonal bipyramids, and faces with four equivalent Se(1)Pm4Se4 hexagonal bipyramids. In the second Se site, Se(2) is bonded in a square co-planar geometry to four equivalent Pm(1) atoms. is represented by the CIF card [CIF]
data_PmSe3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.132
_cell_length_b   6.132
_cell_length_c   6.132
_cell_angle_alpha   140.325
_cell_angle_beta   140.325
_cell_angle_gamma   57.361
_symmetry_Int_Tables_number   1
_cell_volume   93.175
_cell_formula_units_Z   1
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  0.000  0.000  0.000  1.0
  Se  Se1  1  0.750  0.250  0.500  1.0
  Se  Se2  1  0.250  0.750  0.500  1.0
  Se  Se3  1  0.500  0.500  0.000  1.0
[/CIF]
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The structure described by PmSe3 crystallizes in the tetragonal I4/mmm space group. Pm(1) is bonded to four equivalent Se(2) and eight equivalent Se(1) atoms to form distorted PmSe12 cuboctahedra that share corners with four equivalent Pm(1)Se12 cuboctahedra, corners with sixteen equivalent Se(1)Pm4Se4 hexagonal bipyramids, edges with eight equivalent Pm(1)Se12 cuboctahedra, edges with eight equivalent Se(1)Pm4Se4 hexagonal bipyramids, and faces with four equivalent Pm(1)Se12 cuboctahedra. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to four equivalent Pm(1) and four equivalent Se(1) atoms to form distorted SePm4Se4 hexagonal bipyramids that share corners with eight equivalent Pm(1)Se12 cuboctahedra, corners with sixteen equivalent Se(1)Pm4Se4 hexagonal bipyramids, edges with four equivalent Pm(1)Se12 cuboctahedra, edges with six equivalent Se(1)Pm4Se4 hexagonal bipyramids, and faces with four equivalent Se(1)Pm4Se4 hexagonal bipyramids. In the second Se site, Se(2) is bonded in a square co-planar geometry to four equivalent Pm(1) atoms. is represented by the CIF card [CIF]
data_PmSe3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.132
_cell_length_b   6.132
_cell_length_c   6.132
_cell_angle_alpha   140.325
_cell_angle_beta   140.325
_cell_angle_gamma   57.361
_symmetry_Int_Tables_number   1
_cell_volume   93.175
_cell_formula_units_Z   1
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  0.000  0.000  0.000  1.0
  Se  Se1  1  0.750  0.250  0.500  1.0
  Se  Se2  1  0.250  0.750  0.500  1.0
  Se  Se3  1  0.500  0.500  0.000  1.0
[/CIF]
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