The compound described by Sm5CuSe8 crystallizes in the tetragonal I-4 space group. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 8-coordinate geometry to four equivalent Se(1) and four equivalent Se(2) atoms. In the second Sm site, Sm(2) is bonded in a 8-coordinate geometry to four equivalent Se(1) and four equivalent Se(2) atoms. Cu(1) is bonded in a square co-planar geometry to four equivalent Se(1) atoms. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to one Sm(2), four equivalent Sm(1), and one Cu(1) atom to form distorted SeSm5Cu octahedra that share corners with seven equivalent Se(1)Sm5Cu octahedra, corners with eight equivalent Se(2)Sm5 square pyramids, edges with four equivalent Se(1)Sm5Cu octahedra, edges with three equivalent Se(2)Sm5 square pyramids,  a faceface with one Se(1)Sm5Cu octahedra, and faces with two equivalent Se(2)Sm5 square pyramids. The corner-sharing octahedral tilt angles range from 17-47°. In the second Se site, Se(2) is bonded to one Sm(2) and four equivalent Sm(1) atoms to form distorted SeSm5 square pyramids that share corners with eight equivalent Se(1)Sm5Cu octahedra, corners with five equivalent Se(2)Sm5 square pyramids, edges with three equivalent Se(1)Sm5Cu octahedra, edges with five equivalent Se(2)Sm5 square pyramids, and faces with two equivalent Se(1)Sm5Cu octahedra. The corner-sharing octahedral tilt angles range from 20-89°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Sm5CuSe8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.630
_cell_length_b   7.630
_cell_length_c   7.630
_cell_angle_alpha   110.268
_cell_angle_beta   110.268
_cell_angle_gamma   107.888
_symmetry_Int_Tables_number   1
_cell_volume   341.759
_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
  Sm  Sm0  1  0.367  0.989  0.118  1.0
  Sm  Sm1  1  0.011  0.129  0.378  1.0
  Sm  Sm2  1  0.871  0.249  0.882  1.0
  Sm  Sm3  1  0.500  0.500  0.000  1.0
  Sm  Sm4  1  0.751  0.633  0.622  1.0
  Cu  Cu5  1  0.250  0.750  0.500  1.0
  Se  Se6  1  0.269  0.398  0.260  1.0
  Se  Se7  1  0.139  0.010  0.740  1.0
  Se  Se8  1  0.491  0.249  0.607  1.0
  Se  Se9  1  0.116  0.509  0.759  1.0
  Se  Se10  1  0.751  0.358  0.241  1.0
  Se  Se11  1  0.602  0.861  0.871  1.0
  Se  Se12  1  0.990  0.731  0.129  1.0
  Se  Se13  1  0.642  0.884  0.393  1.0
[/CIF]
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The compound described by Sm5CuSe8 crystallizes in the tetragonal I-4 space group. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 8-coordinate geometry to four equivalent Se(1) and four equivalent Se(2) atoms. In the second Sm site, Sm(2) is bonded in a 8-coordinate geometry to four equivalent Se(1) and four equivalent Se(2) atoms. Cu(1) is bonded in a square co-planar geometry to four equivalent Se(1) atoms. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to one Sm(2), four equivalent Sm(1), and one Cu(1) atom to form distorted SeSm5Cu octahedra that share corners with seven equivalent Se(1)Sm5Cu octahedra, corners with eight equivalent Se(2)Sm5 square pyramids, edges with four equivalent Se(1)Sm5Cu octahedra, edges with three equivalent Se(2)Sm5 square pyramids,  a faceface with one Se(1)Sm5Cu octahedra, and faces with two equivalent Se(2)Sm5 square pyramids. The corner-sharing octahedral tilt angles range from 17-47°. In the second Se site, Se(2) is bonded to one Sm(2) and four equivalent Sm(1) atoms to form distorted SeSm5 square pyramids that share corners with eight equivalent Se(1)Sm5Cu octahedra, corners with five equivalent Se(2)Sm5 square pyramids, edges with three equivalent Se(1)Sm5Cu octahedra, edges with five equivalent Se(2)Sm5 square pyramids, and faces with two equivalent Se(1)Sm5Cu octahedra. The corner-sharing octahedral tilt angles range from 20-89°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Sm5CuSe8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.630
_cell_length_b   7.630
_cell_length_c   7.630
_cell_angle_alpha   110.268
_cell_angle_beta   110.268
_cell_angle_gamma   107.888
_symmetry_Int_Tables_number   1
_cell_volume   341.759
_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
  Sm  Sm0  1  0.367  0.989  0.118  1.0
  Sm  Sm1  1  0.011  0.129  0.378  1.0
  Sm  Sm2  1  0.871  0.249  0.882  1.0
  Sm  Sm3  1  0.500  0.500  0.000  1.0
  Sm  Sm4  1  0.751  0.633  0.622  1.0
  Cu  Cu5  1  0.250  0.750  0.500  1.0
  Se  Se6  1  0.269  0.398  0.260  1.0
  Se  Se7  1  0.139  0.010  0.740  1.0
  Se  Se8  1  0.491  0.249  0.607  1.0
  Se  Se9  1  0.116  0.509  0.759  1.0
  Se  Se10  1  0.751  0.358  0.241  1.0
  Se  Se11  1  0.602  0.861  0.871  1.0
  Se  Se12  1  0.990  0.731  0.129  1.0
  Se  Se13  1  0.642  0.884  0.393  1.0
[/CIF]
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