The structure described by Pb4SnSe5 is Caswellsilverite-like structured and crystallizes in the trigonal R-3m space group. There are two inequivalent Pb sites. In the first Pb site, Pb(1) is bonded to three equivalent Se(1) and three equivalent Se(3) atoms to form PbSe6 octahedra that share corners with three equivalent Pb(2)Se6 octahedra, corners with three equivalent Sn(1)Se6 octahedra, edges with three equivalent Pb(2)Se6 octahedra, edges with three equivalent Sn(1)Se6 octahedra, and edges with six equivalent Pb(1)Se6 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. In the second Pb site, Pb(2) is bonded to three equivalent Se(2) and three equivalent Se(3) atoms to form a mixture of corner and edge-sharing PbSe6 octahedra. The corner-sharing octahedra are not tilted. Sn(1) is bonded to six equivalent Se(1) atoms to form SnSe6 octahedra that share corners with six equivalent Pb(1)Se6 octahedra, edges with six equivalent Pb(1)Se6 octahedra, and edges with six equivalent Sn(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to three equivalent Pb(1) and three equivalent Sn(1) atoms to form SeSn3Pb3 octahedra that share corners with three equivalent Se(3)Pb6 octahedra, corners with three equivalent Se(1)Sn3Pb3 octahedra, edges with three equivalent Se(3)Pb6 octahedra, and edges with nine equivalent Se(1)Sn3Pb3 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the second Se site, Se(2) is bonded to six equivalent Pb(2) atoms to form a mixture of corner and edge-sharing SePb6 octahedra. The corner-sharing octahedra are not tilted. In the third Se site, Se(3) is bonded to three equivalent Pb(1) and three equivalent Pb(2) atoms to form SePb6 octahedra that share corners with three equivalent Se(2)Pb6 octahedra, corners with three equivalent Se(1)Sn3Pb3 octahedra, edges with three equivalent Se(2)Pb6 octahedra, edges with three equivalent Se(1)Sn3Pb3 octahedra, and edges with six equivalent Se(3)Pb6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. is represented by the CIF file [CIF]
data_SnPb4Se5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   17.815
_cell_length_b   17.815
_cell_length_c   17.815
_cell_angle_alpha   14.163
_cell_angle_beta   14.163
_cell_angle_gamma   14.163
_symmetry_Int_Tables_number   1
_cell_volume   294.681
_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
  Sn  Sn0  1  0.000  0.000  0.000  1.0
  Pb  Pb1  1  0.600  0.600  0.600  1.0
  Pb  Pb2  1  0.200  0.200  0.200  1.0
  Pb  Pb3  1  0.800  0.800  0.800  1.0
  Pb  Pb4  1  0.400  0.400  0.400  1.0
  Se  Se5  1  0.699  0.699  0.699  1.0
  Se  Se6  1  0.500  0.500  0.500  1.0
  Se  Se7  1  0.100  0.100  0.100  1.0
  Se  Se8  1  0.301  0.301  0.301  1.0
  Se  Se9  1  0.900  0.900  0.900  1.0
[/CIF]
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The structure described by Pb4SnSe5 is Caswellsilverite-like structured and crystallizes in the trigonal R-3m space group. There are two inequivalent Pb sites. In the first Pb site, Pb(1) is bonded to three equivalent Se(1) and three equivalent Se(3) atoms to form PbSe6 octahedra that share corners with three equivalent Pb(2)Se6 octahedra, corners with three equivalent Sn(1)Se6 octahedra, edges with three equivalent Pb(2)Se6 octahedra, edges with three equivalent Sn(1)Se6 octahedra, and edges with six equivalent Pb(1)Se6 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. In the second Pb site, Pb(2) is bonded to three equivalent Se(2) and three equivalent Se(3) atoms to form a mixture of corner and edge-sharing PbSe6 octahedra. The corner-sharing octahedra are not tilted. Sn(1) is bonded to six equivalent Se(1) atoms to form SnSe6 octahedra that share corners with six equivalent Pb(1)Se6 octahedra, edges with six equivalent Pb(1)Se6 octahedra, and edges with six equivalent Sn(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to three equivalent Pb(1) and three equivalent Sn(1) atoms to form SeSn3Pb3 octahedra that share corners with three equivalent Se(3)Pb6 octahedra, corners with three equivalent Se(1)Sn3Pb3 octahedra, edges with three equivalent Se(3)Pb6 octahedra, and edges with nine equivalent Se(1)Sn3Pb3 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the second Se site, Se(2) is bonded to six equivalent Pb(2) atoms to form a mixture of corner and edge-sharing SePb6 octahedra. The corner-sharing octahedra are not tilted. In the third Se site, Se(3) is bonded to three equivalent Pb(1) and three equivalent Pb(2) atoms to form SePb6 octahedra that share corners with three equivalent Se(2)Pb6 octahedra, corners with three equivalent Se(1)Sn3Pb3 octahedra, edges with three equivalent Se(2)Pb6 octahedra, edges with three equivalent Se(1)Sn3Pb3 octahedra, and edges with six equivalent Se(3)Pb6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. is represented by the CIF file [CIF]
data_SnPb4Se5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   17.815
_cell_length_b   17.815
_cell_length_c   17.815
_cell_angle_alpha   14.163
_cell_angle_beta   14.163
_cell_angle_gamma   14.163
_symmetry_Int_Tables_number   1
_cell_volume   294.681
_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
  Sn  Sn0  1  0.000  0.000  0.000  1.0
  Pb  Pb1  1  0.600  0.600  0.600  1.0
  Pb  Pb2  1  0.200  0.200  0.200  1.0
  Pb  Pb3  1  0.800  0.800  0.800  1.0
  Pb  Pb4  1  0.400  0.400  0.400  1.0
  Se  Se5  1  0.699  0.699  0.699  1.0
  Se  Se6  1  0.500  0.500  0.500  1.0
  Se  Se7  1  0.100  0.100  0.100  1.0
  Se  Se8  1  0.301  0.301  0.301  1.0
  Se  Se9  1  0.900  0.900  0.900  1.0
[/CIF]
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