The material described by CsBi4Se7 crystallizes in the monoclinic C2/m space group. Cs(1) is bonded in a 6-coordinate geometry to one Se(4), one Se(6), two equivalent Se(1), and two equivalent Se(5) atoms. There are four inequivalent Bi sites. In the first Bi site, Bi(1) is bonded to one Se(4), one Se(6), two equivalent Se(3), and two equivalent Se(7) atoms to form a mixture of corner and edge-sharing BiSe6 octahedra. The corner-sharing octahedral tilt angles range from 5-6°. In the second Bi site, Bi(2) is bonded to one Se(2), one Se(3), two equivalent Se(1), and two equivalent Se(6) atoms to form a mixture of corner and edge-sharing BiSe6 octahedra. The corner-sharing octahedral tilt angles are 3°. In the third Bi site, Bi(3) is bonded to one Se(1), two equivalent Se(4), and three equivalent Se(3) atoms to form a mixture of corner and edge-sharing BiSe6 octahedra. The corner-sharing octahedral tilt angles range from 3-6°. In the fourth Bi site, Bi(4) is bonded to one Se(6), two equivalent Se(2), and three equivalent Se(5) atoms to form a mixture of distorted corner and edge-sharing BiSe6 octahedra. The corner-sharing octahedral tilt angles are 5°. There are seven inequivalent Se sites. In the first Se site, Se(7) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Bi(1) and one Se(7) atom. In the second Se site, Se(1) is bonded to two equivalent Cs(1), one Bi(3), and two equivalent Bi(2) atoms to form SeCs2Bi3 square pyramids that share  a cornercorner with one Se(3)Bi6 octahedra, corners with two equivalent Se(5)Cs2Bi3 trigonal bipyramids, corners with four equivalent Se(6)CsBi4 trigonal bipyramids, edges with two equivalent Se(3)Bi6 octahedra, edges with two equivalent Se(1)Cs2Bi3 square pyramids,  an edgeedge with one Se(5)Cs2Bi3 trigonal bipyramid, and  an edgeedge with one Se(6)CsBi4 trigonal bipyramid. The corner-sharing octahedral tilt angles are 7°. In the third Se site, Se(2) is bonded in a distorted T-shaped geometry to one Bi(2) and two equivalent Bi(4) atoms. In the fourth Se site, Se(3) is bonded to one Bi(2), two equivalent Bi(1), and three equivalent Bi(3) atoms to form SeBi6 octahedra that share  a cornercorner with one Se(1)Cs2Bi3 square pyramid, edges with four equivalent Se(3)Bi6 octahedra, edges with two equivalent Se(1)Cs2Bi3 square pyramids, and edges with two equivalent Se(6)CsBi4 trigonal bipyramids. In the fifth Se site, Se(4) is bonded in a see-saw-like geometry to one Cs(1), one Bi(1), and two equivalent Bi(3) atoms. In the sixth Se site, Se(5) is bonded to two equivalent Cs(1) and three equivalent Bi(4) atoms to form distorted SeCs2Bi3 trigonal bipyramids that share corners with two equivalent Se(1)Cs2Bi3 square pyramids,  a cornercorner with one Se(6)CsBi4 trigonal bipyramid,  an edgeedge with one Se(1)Cs2Bi3 square pyramid, edges with two equivalent Se(6)CsBi4 trigonal bipyramids, and edges with four equivalent Se(5)Cs2Bi3 trigonal bipyramids. In the seventh Se site, Se(6) is bonded to one Cs(1), one Bi(1), one Bi(4), and two equivalent Bi(2) atoms to form distorted SeCsBi4 trigonal bipyramids that share corners with four equivalent Se(1)Cs2Bi3 square pyramids,  a cornercorner with one Se(5)Cs2Bi3 trigonal bipyramid, corners with two equivalent Se(6)CsBi4 trigonal bipyramids, edges with two equivalent Se(3)Bi6 octahedra,  an edgeedge with one Se(1)Cs2Bi3 square pyramid, and edges with two equivalent Se(5)Cs2Bi3 trigonal bipyramids. is represented by the CIF card [CIF]
data_CsBi4Se7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.105
_cell_length_b   11.105
_cell_length_c   19.812
_cell_angle_alpha   64.691
_cell_angle_beta   64.691
_cell_angle_gamma   23.139
_symmetry_Int_Tables_number   1
_cell_volume   863.909
_cell_formula_units_Z   2
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
  Cs  Cs0  1  0.461  0.461  0.794  1.0
  Cs  Cs1  1  0.539  0.539  0.206  1.0
  Bi  Bi2  1  0.635  0.635  0.429  1.0
  Bi  Bi3  1  0.365  0.365  0.571  1.0
  Bi  Bi4  1  0.712  0.712  0.754  1.0
  Bi  Bi5  1  0.288  0.288  0.246  1.0
  Bi  Bi6  1  0.161  0.161  0.600  1.0
  Bi  Bi7  1  0.839  0.839  0.400  1.0
  Bi  Bi8  1  0.235  0.235  0.921  1.0
  Bi  Bi9  1  0.765  0.765  0.079  1.0
  Se  Se10  1  0.118  0.118  0.755  1.0
  Se  Se11  1  0.882  0.882  0.245  1.0
  Se  Se12  1  0.653  0.653  0.909  1.0
  Se  Se13  1  0.347  0.347  0.091  1.0
  Se  Se14  1  0.772  0.772  0.577  1.0
  Se  Se15  1  0.228  0.228  0.423  1.0
  Se  Se16  1  0.581  0.581  0.596  1.0
  Se  Se17  1  0.419  0.419  0.404  1.0
  Se  Se18  1  0.831  0.831  0.925  1.0
  Se  Se19  1  0.169  0.169  0.075  1.0
  Se  Se20  1  0.311  0.311  0.734  1.0
  Se  Se21  1  0.689  0.689  0.266  1.0
  Se  Se22  1  0.039  0.039  0.436  1.0
  Se  Se23  1  0.961  0.961  0.564  1.0
[/CIF]
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The material described by CsBi4Se7 crystallizes in the monoclinic C2/m space group. Cs(1) is bonded in a 6-coordinate geometry to one Se(4), one Se(6), two equivalent Se(1), and two equivalent Se(5) atoms. There are four inequivalent Bi sites. In the first Bi site, Bi(1) is bonded to one Se(4), one Se(6), two equivalent Se(3), and two equivalent Se(7) atoms to form a mixture of corner and edge-sharing BiSe6 octahedra. The corner-sharing octahedral tilt angles range from 5-6°. In the second Bi site, Bi(2) is bonded to one Se(2), one Se(3), two equivalent Se(1), and two equivalent Se(6) atoms to form a mixture of corner and edge-sharing BiSe6 octahedra. The corner-sharing octahedral tilt angles are 3°. In the third Bi site, Bi(3) is bonded to one Se(1), two equivalent Se(4), and three equivalent Se(3) atoms to form a mixture of corner and edge-sharing BiSe6 octahedra. The corner-sharing octahedral tilt angles range from 3-6°. In the fourth Bi site, Bi(4) is bonded to one Se(6), two equivalent Se(2), and three equivalent Se(5) atoms to form a mixture of distorted corner and edge-sharing BiSe6 octahedra. The corner-sharing octahedral tilt angles are 5°. There are seven inequivalent Se sites. In the first Se site, Se(7) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Bi(1) and one Se(7) atom. In the second Se site, Se(1) is bonded to two equivalent Cs(1), one Bi(3), and two equivalent Bi(2) atoms to form SeCs2Bi3 square pyramids that share  a cornercorner with one Se(3)Bi6 octahedra, corners with two equivalent Se(5)Cs2Bi3 trigonal bipyramids, corners with four equivalent Se(6)CsBi4 trigonal bipyramids, edges with two equivalent Se(3)Bi6 octahedra, edges with two equivalent Se(1)Cs2Bi3 square pyramids,  an edgeedge with one Se(5)Cs2Bi3 trigonal bipyramid, and  an edgeedge with one Se(6)CsBi4 trigonal bipyramid. The corner-sharing octahedral tilt angles are 7°. In the third Se site, Se(2) is bonded in a distorted T-shaped geometry to one Bi(2) and two equivalent Bi(4) atoms. In the fourth Se site, Se(3) is bonded to one Bi(2), two equivalent Bi(1), and three equivalent Bi(3) atoms to form SeBi6 octahedra that share  a cornercorner with one Se(1)Cs2Bi3 square pyramid, edges with four equivalent Se(3)Bi6 octahedra, edges with two equivalent Se(1)Cs2Bi3 square pyramids, and edges with two equivalent Se(6)CsBi4 trigonal bipyramids. In the fifth Se site, Se(4) is bonded in a see-saw-like geometry to one Cs(1), one Bi(1), and two equivalent Bi(3) atoms. In the sixth Se site, Se(5) is bonded to two equivalent Cs(1) and three equivalent Bi(4) atoms to form distorted SeCs2Bi3 trigonal bipyramids that share corners with two equivalent Se(1)Cs2Bi3 square pyramids,  a cornercorner with one Se(6)CsBi4 trigonal bipyramid,  an edgeedge with one Se(1)Cs2Bi3 square pyramid, edges with two equivalent Se(6)CsBi4 trigonal bipyramids, and edges with four equivalent Se(5)Cs2Bi3 trigonal bipyramids. In the seventh Se site, Se(6) is bonded to one Cs(1), one Bi(1), one Bi(4), and two equivalent Bi(2) atoms to form distorted SeCsBi4 trigonal bipyramids that share corners with four equivalent Se(1)Cs2Bi3 square pyramids,  a cornercorner with one Se(5)Cs2Bi3 trigonal bipyramid, corners with two equivalent Se(6)CsBi4 trigonal bipyramids, edges with two equivalent Se(3)Bi6 octahedra,  an edgeedge with one Se(1)Cs2Bi3 square pyramid, and edges with two equivalent Se(5)Cs2Bi3 trigonal bipyramids. is represented by the CIF card [CIF]
data_CsBi4Se7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.105
_cell_length_b   11.105
_cell_length_c   19.812
_cell_angle_alpha   64.691
_cell_angle_beta   64.691
_cell_angle_gamma   23.139
_symmetry_Int_Tables_number   1
_cell_volume   863.909
_cell_formula_units_Z   2
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
  Cs  Cs0  1  0.461  0.461  0.794  1.0
  Cs  Cs1  1  0.539  0.539  0.206  1.0
  Bi  Bi2  1  0.635  0.635  0.429  1.0
  Bi  Bi3  1  0.365  0.365  0.571  1.0
  Bi  Bi4  1  0.712  0.712  0.754  1.0
  Bi  Bi5  1  0.288  0.288  0.246  1.0
  Bi  Bi6  1  0.161  0.161  0.600  1.0
  Bi  Bi7  1  0.839  0.839  0.400  1.0
  Bi  Bi8  1  0.235  0.235  0.921  1.0
  Bi  Bi9  1  0.765  0.765  0.079  1.0
  Se  Se10  1  0.118  0.118  0.755  1.0
  Se  Se11  1  0.882  0.882  0.245  1.0
  Se  Se12  1  0.653  0.653  0.909  1.0
  Se  Se13  1  0.347  0.347  0.091  1.0
  Se  Se14  1  0.772  0.772  0.577  1.0
  Se  Se15  1  0.228  0.228  0.423  1.0
  Se  Se16  1  0.581  0.581  0.596  1.0
  Se  Se17  1  0.419  0.419  0.404  1.0
  Se  Se18  1  0.831  0.831  0.925  1.0
  Se  Se19  1  0.169  0.169  0.075  1.0
  Se  Se20  1  0.311  0.311  0.734  1.0
  Se  Se21  1  0.689  0.689  0.266  1.0
  Se  Se22  1  0.039  0.039  0.436  1.0
  Se  Se23  1  0.961  0.961  0.564  1.0
[/CIF]
.