The material structure described by Cs3Er2Br9 crystallizes in the trigonal R-3c space group. Cs(1) is bonded to four equivalent Br(1) and eight equivalent Br(2) atoms to form CsBr12 cuboctahedra that share corners with six equivalent Cs(1)Br12 cuboctahedra, corners with four equivalent Er(1)Br6 octahedra, faces with eight equivalent Cs(1)Br12 cuboctahedra, and faces with four equivalent Er(1)Br6 octahedra. The corner-sharing octahedral tilt angles range from 12-30°. Er(1) is bonded to three equivalent Br(1) and three equivalent Br(2) atoms to form ErBr6 octahedra that share corners with six equivalent Cs(1)Br12 cuboctahedra, faces with six equivalent Cs(1)Br12 cuboctahedra, and  a faceface with one Er(1)Br6 octahedra. There are two inequivalent Br sites. In the first Br site, Br(2) is bonded in a distorted single-bond geometry to four equivalent Cs(1) and one Er(1) atom. In the second Br site, Br(1) is bonded in a distorted L-shaped geometry to four equivalent Cs(1) and two equivalent Er(1) atoms. is represented by the CIF file [CIF]
data_Cs3Er2Br9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.233
_cell_length_b   10.232
_cell_length_c   10.233
_cell_angle_alpha   83.785
_cell_angle_beta   83.784
_cell_angle_gamma   83.780
_symmetry_Int_Tables_number   1
_cell_volume   1053.796
_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  0.590  0.910  0.250  1.0
  Cs  Cs1  1  0.250  0.590  0.910  1.0
  Cs  Cs2  1  0.910  0.250  0.590  1.0
  Cs  Cs3  1  0.750  0.410  0.090  1.0
  Cs  Cs4  1  0.090  0.750  0.410  1.0
  Cs  Cs5  1  0.410  0.090  0.750  1.0
  Er  Er6  1  0.848  0.848  0.848  1.0
  Er  Er7  1  0.348  0.348  0.348  1.0
  Er  Er8  1  0.152  0.152  0.152  1.0
  Er  Er9  1  0.652  0.652  0.652  1.0
  Br  Br10  1  0.094  0.406  0.250  1.0
  Br  Br11  1  0.250  0.094  0.406  1.0
  Br  Br12  1  0.406  0.250  0.094  1.0
  Br  Br13  1  0.750  0.906  0.594  1.0
  Br  Br14  1  0.594  0.750  0.906  1.0
  Br  Br15  1  0.906  0.594  0.750  1.0
  Br  Br16  1  0.236  0.418  0.583  1.0
  Br  Br17  1  0.583  0.236  0.418  1.0
  Br  Br18  1  0.418  0.583  0.236  1.0
  Br  Br19  1  0.083  0.918  0.736  1.0
  Br  Br20  1  0.736  0.083  0.918  1.0
  Br  Br21  1  0.918  0.736  0.083  1.0
  Br  Br22  1  0.764  0.582  0.417  1.0
  Br  Br23  1  0.417  0.764  0.582  1.0
  Br  Br24  1  0.582  0.417  0.764  1.0
  Br  Br25  1  0.917  0.082  0.264  1.0
  Br  Br26  1  0.264  0.917  0.082  1.0
  Br  Br27  1  0.082  0.264  0.917  1.0
[/CIF]
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The material structure described by Cs3Er2Br9 crystallizes in the trigonal R-3c space group. Cs(1) is bonded to four equivalent Br(1) and eight equivalent Br(2) atoms to form CsBr12 cuboctahedra that share corners with six equivalent Cs(1)Br12 cuboctahedra, corners with four equivalent Er(1)Br6 octahedra, faces with eight equivalent Cs(1)Br12 cuboctahedra, and faces with four equivalent Er(1)Br6 octahedra. The corner-sharing octahedral tilt angles range from 12-30°. Er(1) is bonded to three equivalent Br(1) and three equivalent Br(2) atoms to form ErBr6 octahedra that share corners with six equivalent Cs(1)Br12 cuboctahedra, faces with six equivalent Cs(1)Br12 cuboctahedra, and  a faceface with one Er(1)Br6 octahedra. There are two inequivalent Br sites. In the first Br site, Br(2) is bonded in a distorted single-bond geometry to four equivalent Cs(1) and one Er(1) atom. In the second Br site, Br(1) is bonded in a distorted L-shaped geometry to four equivalent Cs(1) and two equivalent Er(1) atoms. is represented by the CIF file [CIF]
data_Cs3Er2Br9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.233
_cell_length_b   10.232
_cell_length_c   10.233
_cell_angle_alpha   83.785
_cell_angle_beta   83.784
_cell_angle_gamma   83.780
_symmetry_Int_Tables_number   1
_cell_volume   1053.796
_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  0.590  0.910  0.250  1.0
  Cs  Cs1  1  0.250  0.590  0.910  1.0
  Cs  Cs2  1  0.910  0.250  0.590  1.0
  Cs  Cs3  1  0.750  0.410  0.090  1.0
  Cs  Cs4  1  0.090  0.750  0.410  1.0
  Cs  Cs5  1  0.410  0.090  0.750  1.0
  Er  Er6  1  0.848  0.848  0.848  1.0
  Er  Er7  1  0.348  0.348  0.348  1.0
  Er  Er8  1  0.152  0.152  0.152  1.0
  Er  Er9  1  0.652  0.652  0.652  1.0
  Br  Br10  1  0.094  0.406  0.250  1.0
  Br  Br11  1  0.250  0.094  0.406  1.0
  Br  Br12  1  0.406  0.250  0.094  1.0
  Br  Br13  1  0.750  0.906  0.594  1.0
  Br  Br14  1  0.594  0.750  0.906  1.0
  Br  Br15  1  0.906  0.594  0.750  1.0
  Br  Br16  1  0.236  0.418  0.583  1.0
  Br  Br17  1  0.583  0.236  0.418  1.0
  Br  Br18  1  0.418  0.583  0.236  1.0
  Br  Br19  1  0.083  0.918  0.736  1.0
  Br  Br20  1  0.736  0.083  0.918  1.0
  Br  Br21  1  0.918  0.736  0.083  1.0
  Br  Br22  1  0.764  0.582  0.417  1.0
  Br  Br23  1  0.417  0.764  0.582  1.0
  Br  Br24  1  0.582  0.417  0.764  1.0
  Br  Br25  1  0.917  0.082  0.264  1.0
  Br  Br26  1  0.264  0.917  0.082  1.0
  Br  Br27  1  0.082  0.264  0.917  1.0
[/CIF]
.